Damage Calculations

The main goal of the game is to sink Abyssals. Abyssals are sunk by doing Damage to them. This page lists all the applicable formulas and mechanics that affect the calculation of Damage.

Please note that all formulas between [math]\displaystyle{ \lfloor \ \rfloor }[/math] or marked with [math]\displaystyle{ \downarrow }[/math] are rounded down.

• For example, [math]\displaystyle{ \lfloor 4.2 \rfloor = 4 }[/math].
• [math]\displaystyle{ 4.2 \times_\downarrow 1.5 = \lfloor 4.2 \times 1.5 \rfloor = \lfloor 6.3 \rfloor = 6 }[/math], but [math]\displaystyle{ 4.2 \times_\downarrow 1 = 4.2 }[/math] (by definition, [math]\displaystyle{ \times_\downarrow }[/math] is then a non-commutative non-associative operator, it is assumed to be left-associative with lower priority than the usual multiplication operator).
  • [math]\displaystyle{ \times_\downarrow }[/math] is used when the round down applies only when the modifier is applied.

Damage Formula

The Damage is the reduction of HP caused by an attack hitting a target. The formula is the same for all attacks as well as abyssals. It stems from the difference between the final attack power of the assailant and the defense power of the target.

Damage Formula
[math]\displaystyle{ \text{Damage} = \biggl \lfloor \biggl ( \text{Atk}_\text{post-cap} - \text{DEF} \biggr ) \times \text{Ammo} \biggr \rfloor }[/math] With [math]\displaystyle{ \text{Atk}_\text{post-cap} }[/math] the final attack power of the assailant after the cap and all the modifiers have been applied, described below, [math]\displaystyle{ \text{DEF} }[/math] the defensive power of the target, [math]\displaystyle{ \text{Ammo} }[/math] the remaining ammunition modifier.
Notes If [math]\displaystyle{ \text{Atk}_\text{post-cap} }[/math] is inferior to [math]\displaystyle{ \text{DEF} }[/math] or if [math]\displaystyle{ \text{Ammo}=0 }[/math] then the attacks will deal "scratch damage".

Defense Power

Defense power represents the ability of a ship to resist damage. It's calculated from the Armor plus a random element.

Defence Formula
[math]\displaystyle{ \text{DEF} = \left( \text{Armor} \times 0.7 + \text{Armor}_\text{rand} \times 0.6 \right) - \text{Pen} }[/math] With [math]\displaystyle{ \text{Armor} }[/math] the armor of the target including all equipment and upgrade bonuses, [math]\displaystyle{ \text{Armor}_\text{rand} }[/math] a random number between [math]\displaystyle{ 0 }[/math] and [math]\displaystyle{ \lfloor\text{Armor}\rfloor - 1 }[/math], Note that it is inclusive, meaning it can also output [math]\displaystyle{ 0 }[/math] and [math]\displaystyle{ \lfloor\text{Armor}\rfloor - 1 }[/math] [math]\displaystyle{ \text{Pen} }[/math] any applicable armor penetration mechanic: See ASW for details on ASW armor penetration, Some debuffs may include armor penetration.
Notes The range of armor values is uniformly distributed, every armor roll has the same chance of occurring.

For short, defensive power randomly varies between 1.3 x and 0.7 x.

Attacks Power

Attack power represents the ability of a ship to inflict damage. It's affected by a lot of different elements (stats, mechanics, "battle state", etc.) through 4 steps of calcul:

1. Basic
   • Generally calculated from the relevant stats of the ship using different formulas according to the type of attack and the phase of battle
2. Pre-cap
   • The basic attack goes through different modifiers
3. Cap
   • If the attack is superior to a cap it's reduced
4. Post-cap
   • These modifiers are more potent because they are not limited by the cap

Attack Step Formulas
Pre-cap	[math]\displaystyle{ \text{Atk}_\text{pre-cap} = \text{Atk}_\text{base} \times \text{Mod}_\text{pre-cap} }[/math] With [math]\displaystyle{ \text{Atk}_\text{base} }[/math] is the basic attack power of the relevant attack. [math]\displaystyle{ \text{Mod}_\text{pre} }[/math] is any pre-cap modifiers that are applicable.
Cap	The attack is then capped as follows: [math]\displaystyle{ \text{Atk}_\text{cap} = \text{Cap} + \sqrt{\text{Atk}_\text{pre-cap} - \text{Cap}} }[/math] With [math]\displaystyle{ \text{Cap} }[/math] is the damage cap relevant to the phase. [math]\displaystyle{ Cap }[/math] Attack Type Cap Support Expeditions 170 ASW Airstrike Opening Torpedo Salvo 180 Closing Torpedo Salvo LBAS 220 Day shelling Night battle 360
Post-cap	Capped attack is then modified by post-cap modifiers: [math]\displaystyle{ \text{Atk}_\text{post-cap} = \lfloor \text{Atk}_\text{cap} \rfloor \times \text{Mod}_\text{spotting} \times \text{Mod}_\text{CVCI} \times_\downarrow \text{Mod}_\text{AP} \times \text{Mod}_\text{post} \times_\downarrow \text{Crit} }[/math] With [math]\displaystyle{ \text{Atk}_\text{cap} }[/math] the Cap Adjusted Attack Power, [math]\displaystyle{ \text{Mod}_\text{spotting} }[/math] the bonus from artillery spotting, [math]\displaystyle{ \text{Mod}_\text{CVCI} }[/math] the bonus from carrier cut-ins, [math]\displaystyle{ \text{Mod}_\text{AP} }[/math] the bonus from AP shells, The value is rounded down after applying [math]\displaystyle{ \text{Mod}_\text{AP} }[/math] only if the target is able to take extra damage from AP shells, even if [math]\displaystyle{ \text{Mod}_\text{AP} }[/math] is 1 due to the attacker not having AP shells. [math]\displaystyle{ \text{Mod}_\text{post} }[/math] any remaining post-cap modifiers that are applicable, [math]\displaystyle{ \text{Crit} }[/math] the critical modifier, The value is rounded down after applying [math]\displaystyle{ \text{Crit} }[/math] only if the attack is critical.

Basic Attack Power Formulas

The following section details the different formulas to calculate [math]\displaystyle{ \text{Atk}_\text{base} }[/math]. As the formula depends on the type of attacks and the combat phase.

Below are the common variables used in all accuracy formulas:

• [math]\displaystyle{ \text{FP} }[/math] is the Firepower of the ship including equipment.
• [math]\displaystyle{ \text{TP} }[/math] is the Torpedo of the ship including equipment or the torpedo of a plane.
• [math]\displaystyle{ \text{ASW} }[/math] is the Anti-submarine of the ship or equipment.
• [math]\displaystyle{ \text{DB} }[/math] is the Dive bombing of the plane.
• [math]\displaystyle{ \bigstar }[/math] is the upgrade bonus of the equipment.
  • See Improvement or Akashi List for upgrade bonus values.
• [math]\displaystyle{ \text{Plane}_\text{Count} }[/math] is the remaining amount of planes in a slot, performing the attack.
• [math]\displaystyle{ \text{Mod}_\text{CF} }[/math] is the combined fleet modifier based on the tables below:

Combat Phase	Forces	Carrier Task Force	Surface Task Force	Transport Escort Force
Main Fleet Shelling	Allies	+2	+10	-5
	Enemy	+10	+5	+10
Escort Fleet Shelling	Allies	+10	-5	+10
	Enemy	+5	-5	+5
Torpedo	Allies	-5	-5	--5
	Enemy	-5	-5	-5

Combat Phase	Forces	Carrier Task Force	Surface Task Force	Transport Escort Force
Main Fleet Shelling	Allies	+2	+2	-5
	Enemy	+10	+10	+10
Escort Fleet Shelling	Allies	-5	-5	-5
	Enemy	-5	-5	-5
Torpedo	Allies	+10	+10	+10
	Enemy	+10	+10	+10

Combat Phase	Forces	Bonus
Vs Main Fleet	Allies	+5
	Enemy	+10
Vs Escort	Allies	+5
	Enemy	-5
Torpedo	Allies	+10
	Enemy	+10

Airstrike

The damage from airstrikes is calculated independently for each plane slot and mainly depends on the stats of the plane and the current plane count of the slot.

Airstrike Attack Formula
[math]\displaystyle{ \text{Atk}_\text{base airstrike} = \text{Type} \times \biggl( \left( \text{DB or TP} + \bigstar \right) \times \sqrt{\text{Plane}_\text{Count} } + 25 \biggr) }[/math] With [math]\displaystyle{ \text{Type} }[/math] is a multiplier based on the type of the plane. See below for details. [math]\displaystyle{ \text{Type} }[/math] Plane Type Multiplier Notes Torpedo Bombers 0.8x or 1.5x The multiplier is chosen randomly. The chance is roughly 50%. Bomber Dive Bombers Seaplane Bombers 1.0x Jets (During jet assault) 1.0x Jets (During normal bombing) 0.7071x
Notes Airstrike power is calculated independently for each equipment slot on the carrier. The firepower of the carrier does not affect airstrike power. The power is calculated after the air combat and anti-air fire phases which means bombers getting shot down will affect the final calculation. It is not affected by engagement, formation or damage states. It is affected by contact. This applies to Jet Assaults and Airstrikes.

Surface Shelling

The surface shelling damage stems directly from the Firepower of the ship.

Surface Attack Formula
[math]\displaystyle{ \text{Atk}_\text{base shelling} = \text{FP} + \bigstar + \text{Mod}_\text{CF} + 5 }[/math]
Notes The caliber of the gun does not affect damage. Abyssal installations that are not equipped with a plane that has a torpedo or dive bombing stat will use the surface shelling formula for calculating damage. This applies to most ships during the shelling phase.

Carrier Shelling Attacks

Unlike during airstrikes, carrier shelling does not depend on the plane slot and instead combines the stat of the carrier and all planes equipped to one attack.

Carrier Shelling Attack Formula
[math]\displaystyle{ \text{Atk}_\text{base carrier shelling} = \bigl\lfloor \left( \text{FP} + \text{TP} + \bigstar + \left[ \text{DB} \times 1.3 \right] + \text{Mod}_\text{CF} \right) \times 1.5 \bigr\rfloor + 55 }[/math]
Notes Dive and Torpedo groups contribute, respectively, 1.95 and 1.5 times their dive bomb and torpedo stats toward shelling power If a carrier is not equipped with any torpedo or dive bombers, she will not participate in shelling. This also applies if they have lost all bombers during the aerial combat phase. But even if an air group has had all its planes shot down, it will still contribute towards carrier shelling power (if the CV is still capable of attacking). Remember that there are potentially multiple sources of [math]\displaystyle{ \bigstar }[/math] bonuses. Slot sizes and the number of remaining aircraft do not affect carrier attack power during shelling. Carriers have the easiest time hitting the damage cap. This makes them very powerful assets for the fleet. Abyssal installations equipped with a plane that has a torpedo or dive bombing stat will use the carrier formula for determining shelling damage. Planes are not shot down when a carrier participates in shelling. This applies to carriers and Hayasui Kai/Yamashio Maru Kai during the shelling phase.

Torpedo Attacks

Torpedo damage stems directly from the Torpedo of the ship.

Torpedo Attack Formula
[math]\displaystyle{ \text{Atk}_\text{base torpedo} = \text{TP} + \bigstar + \text{Mod}_\text{CF} + 5 }[/math]
Notes Torpedoes cannot target submarines and Abyssal installations. If the only available targets are submarines, the attack will trigger but always miss. If the only available targets are installations, the attack will not trigger. A ship must have a base torpedo stat of more than 0 to perform torpedo attacks. Torpedo Attacks only include the Opening Torpedo Salvo and Closing Torpedo Salvo.

Anti-Submarine Warfare

For more information on this topic, see Anti-Submarine Warfare.

The stats used to calculate damage against submarines is the ASW.

• When contributing to ASW power, Base ASW is square rooted, while equipment ASW is multiplied by 1.5.
  • Anti-submarine weaponry is therefore the primary source of ASW damage, with the base ship ASW playing a very minor role damage-wise.
  • However, base ship ASW is the primary determinant of whether a ship can reach 100 total ASW to perform "Opening ASW" (OASW) attacks.
• Unlike shelling, ASW damage is capped at 170.

ASW attacks have different modifiers gained from Formations,

• Line Abreast is the main ASW formation, with a 1.3x damage modifier,
• Cruising Formation 1 is the main ASW formation for Combined Fleets, with a 1.3x damage modifier.

Anti-Submarine Formula
[math]\displaystyle{ \text{Atk}_\text{base ASW} = \left( 2\sqrt{\text{ASW}_\text{ship} } + 1.5 \times \bigg[ \sum_\text{All Equipment} (\text{ASW}_\text{equip} + \uparrow \text{ASW}_\text{fit bonus} ) \bigg] + \bigstar + \text{Type}_\text{ship} \right) \times \text{Mod}_\text{synergy} }[/math] With [math]\displaystyle{ \text{ASW}_\text{equip} }[/math] is the stat of anti-submarine equipment and attack planes. This means that the stat is not included in the calculation for the following equipment types: Main Guns, Radars, Fighters, Carrier Recons, Recon Seaplane Recons, Seaplane Fighters, Large Flying Boats. [math]\displaystyle{ \uparrow \text{ASW}_\text{fit bonus} }[/math] unlike [math]\displaystyle{ \text{ASW}_\text{equip} }[/math] this is the from Fit Bonuses of all equipment. [math]\displaystyle{ \text{Type}_\text{ship} }[/math] a constant depending on the type of the ship performing the attack. See below for details. Ship Type Constant Ship Types [math]\displaystyle{ \text{Type}_\text{ship} }[/math] Coastal Defense Ships (DE) Destroyers (DD) Light Cruisers (CL/CT) Oilers (AO) (without carrier bomber) 13 Aviation Cruisers (CAV) Aviation Battleships (BBV) Seaplane Tenders (AV) Light Carriers (CVL) Landing Ships (LHA) Oilers (AO) (with carrier bomber) 8 [math]\displaystyle{ \text{Mod}_\text{synergy} }[/math] the synergy multiplier bonus from using certain combinations of ASW equips (see below).
Notes The bonuses do not stack, meaning only the highest possible bonus applies. The exception is the depth charge penetration detailed above. Multiple equipments of the same type still only apply the bonus once. There is an accuracy bonus as well but it is small. Stacking sonars will give a bigger accuracy bonus.

Surface Night Battle

Night battle damage stems directly from the sum of Firepower and Torpedo of the ship.

Night Attack Formula
[math]\displaystyle{ \text{Night Battle Power} = \text{FP} + \text{TP} + \bigstar + \text{Mod}_\text{contact} }[/math] With [math]\displaystyle{ \text{Mod}_\text{contact} }[/math] is the Night Battle Contact if Night Recon is triggered. The value depend of the Accuracy : 5 for 1 , 7 for 2 .
Notes Night battle is unaffected by engagement. Exceptions is Special Attacks. Graf Zeppelin, Base Saratoga, Taiyou-class Kai Ni, Kaga Kai Ni Go, and Ark Royal (with Swordfish) use the surface night battle formula if they are not performing a carrier night attack. In night battle versus Abyssal installations, the torpedo stat is ignored. This also means any upgrade bonuses to torpedo power is ignored. This applies to most ships during Night Battle.

Carrier Night Air Attacks

The carrier night air attack damage calculation is complex but for short only take the stat of the night plane.

Carrier Night Air Attack Formula
[math]\displaystyle{ \text{Night Battle Power}_\text{carrier} = \text{FP}_\text{ship} + \sum_\text{All Night Planes} \text{FP}_\text{night plane} + \text{TP}_\text{night plane} + \text{DB}_\text{night plane} + \text{Night Plane Bonus} }[/math] With [math]\displaystyle{ \text{Night Plane Bonus} }[/math] being: [math]\displaystyle{ \text{Night Plane Bonus} = \mathrm{A} \times \text{Plane}_\text{Count} + \mathrm{B} \times \left( \text{FP}_\text{night plane} + \text{TP}_\text{night plane} + \text{DB}_\text{night plane} + \text{ASW}_\text{night plane} \right) \times \sqrt{\text{Plane}_\text{Count}} + \sqrt{\bigstar} }[/math] [math]\displaystyle{ \mathrm{A} }[/math] is: 3 for Night Planes, 0 for Swordfish , Zero FB Iwai and Suisei Photobomb. [math]\displaystyle{ \mathrm{B} }[/math] is: 0.45 for Night Planes, 0.3 for Swordfish , Zero FB Iwai and Suisei Photobomb.
Notes Unlike daytime carrier attacks, it is possible to attack even if no bombers are equipped. Night fighters are still needed to trigger the attack. Like daytime carrier attacks, carriers are unable to attack if moderately damaged or worse. Armored carriers are only disabled at heavy damage. Carriers that can use the night battle shelling formula will use that instead if moderately damaged. The formula only takes into account the base stats of the carrier and night attack capable planes equipped. The Improvement stats are not taken into account. This means any other stats and upgrade bonuses from equipment like guns and non-night-capable planes are ignored. This also means that any Visible Bonus from Planes is also ignored. The Visible Bonuses given by the SDP+ are whoever counted here. This applies to carrier nigth air attack

Anti-Installation Attacks

For more information on this topic, see Anti-Installation.

Installations differ from regular enemy warships, as they are immune to certain attack elements like the torpedo stat, but are extremely weak against specialized gears.

Support Expedition Attack Power Formula

Support Expedition attack formulas are close but not the same as combat formulas. They also are only affected by the following modifiers:

• Engagement
• Formation
• Criticals

Shelling Support

Basic attack power is calculated in the same way as normal for surface ships and carriers except that firepower is reduced by 1.

Airstrike Support

Airstrike Support Attack Formula
[math]\displaystyle{ \text{Airstrike Support} = \biggl\lfloor \biggl\{ \text{Type} \times \bigl( \left( \text{DB or TP} \right) \times \sqrt{\text{Count}_\text{Plane} } + 3 \bigr) \biggr\} \times \text{Mod}_\text{crit} \biggr\rfloor \times 1.35 }[/math]
Notes The damage cap of 170 is applied to the result between [math]\displaystyle{ \{ \ \} }[/math]. [math]\displaystyle{ \text{Type} }[/math] is the bomber's type modifier, similar to airstrikes. [math]\displaystyle{ 1.0 }[/math] for dive bombers and seaplane bombers. Either [math]\displaystyle{ 0.8 }[/math] or [math]\displaystyle{ 1.5 }[/math] for torpedo bombers. The critical modifier and the 1.35x airstrike support modifier are both post-cap. Is not affected by formation like normal airstrike. The proficiency has no effect on this support.

Anti-Submarine Support

Anti-Submarine Support Attack Formula
[math]\displaystyle{ \text{ASW Support} = \biggl\lfloor \biggl\{ \bigl(\text{ASW} \times \sqrt{\text{Count}_\text{Plane} } + 3 \bigr) \times \left(0.9 + \text{Rand} \right) \biggr\} \times \text{Mod}_\text{crit} \biggr\rfloor \times 1.35 }[/math] With [math]\displaystyle{ \text{Rand} }[/math] a random number from 0 to 0.75 inclusive. The critical modifier and the 1.35x airstrike support modifier are both post-cap. The damage cap of 170 is applied to the result between [math]\displaystyle{ \{ \ \} }[/math].
Notes Because slot size matters, carriers make much better ASW support ships than light carriers. It has a chance of triggering at every node so consider the enemy compositions of all nodes when running ASW support to help with submarine nodes. A full ASW support setup that runs into enemy airpower will get destroyed. Because even the autogyros and liaison aircraft participate in aerial combat, they can be shot down. It can be useful for chipping down submarines to reduce the number of opening and closing torpedoes faced by the fleet.

Long Range Torpedo Support

Long-Range Torpedo Attack Formula
[math]\displaystyle{ \text{Atk}_\text{base torpedo support} = \text{TP} + 8 }[/math] With For this formula it's unknown if [math]\displaystyle{ \text{TP} }[/math] include fit bonus or not.
Notes Do not bother using this type of support, since it is by design inferior to the other ones.

LBAS Attack Power Formulas

For more information on this topic, see LBAS.

Anti-Ship
Pre-cap	[math]\displaystyle{ \text{Atk}_\text{pre-cap} = \biggl\lfloor \text{Mod}_\text{type} \times \Big( \big( \text{Mod}_\text{Sp1} \times \text{TP/DB} + \bigstar + \text{Mod}_\text{Sp2} \big) \times \sqrt{1.8 \times \text{Plane}_\text{Count}} + 25 \Big) \times \text{Mod}_\text{Sp3} \times \text{Mod}_\text{LBR} \biggr\rfloor }[/math] With [math]\displaystyle{ \text{TP/DB} }[/math] the: Torpedo stat for bomber LB Bombers and Torpedo Bombers, Dive bombing stat for Dive Bombers, Jets, Bomber Seaplane Bombers, and Hayabusa ASW Hayabusa . For carrier-based planes and seaplanes having both & stats, the second stat is not used. For aircraft with neither nor stat ( Rotorcraft & Command Liaison Aircraft so far), the formula still works, with minimal effectiveness. The stat does not count for Recon Seaplane Recons and fighters ( Land-based Fighter Jet so far), The effect of the FP stat is unknown yet. [math]\displaystyle{ \bigstar }[/math] the Improvement bonuses of the equipment. Pre-cap modifiers [math]\displaystyle{ \text{Plane}_\text{Count} }[/math] the curent planes count in the slot. It will be 18 (only 9 for LB Heavy Bombers) for fully resupplied bases on their 1st attack. [math]\displaystyle{ \text{Mod}_\text{type} }[/math] the type modifier: 0.8 for other bomber LB Attackers and LB Heavy Bombers 1.0 for Dive Bombers, Torpedo Bombers, Bomber Seaplane Bombers, Rotorcraft, and Anti-submarine Patrol Aircraft, 0.7071 for Jets. [math]\displaystyle{ \text{Mod}_\text{Sp1}, \text{Mod}_\text{Sp2}, \text{Mod}_\text{Sp3} }[/math] the special modifiers for #LBAS Special Bombers on certain targets, For other planes or against other targets, is 1 for Sp1 & Sp3, and 0 for Sp2. [math]\displaystyle{ \text{Mod}_\text{LBR} }[/math] the bonus for having a land-based recon LB present in the base. 1.12 for Type 2 Land-based Reconnaissance Aircraft and Mosquito PR Mk.IV, 1.15 for Type 2 Land-based Reconnaissance Aircraft (Skilled), 1 otherwise. The bonus do not stack. If there are multiple recons in the land-base, only the highest bonus will be applied.
Post-cap	[math]\displaystyle{ \text{Atk}_\text{post-cap} = \biggl\lfloor \text{Atk}_\text{cap} \biggr\rfloor \times \text{Mod}_\text{Contact} \times \text{Mod}_\text{LBB} \times \text{Mod}_\text{CF} \times \text{Mod}_\text{historical} \times \text{Mod}_\text{boss} \times \text{Mod}_\text{balloon} \times_\downarrow \text{Mod}_\text{crit} }[/math] Post-cap modifiers [math]\displaystyle{ \text{Mod}_\text{Contact} }[/math] the contact bonus. Please see Contact for more details on the bonus. [math]\displaystyle{ \text{Mod}_\text{LBB} }[/math] being 1.8 for LB Attackers, and 1.0 otherwise. [math]\displaystyle{ \text{Mod}_\text{CF} }[/math] the bonus when attacking combined fleets. It is 1.1 against combined fleets and 1.0 otherwise. [math]\displaystyle{ \text{Mod}_\text{historical} }[/math] being the event historical bonuses. [math]\displaystyle{ \text{Mod}_\text{boss} }[/math] a bonus when attacking certain Princess and Demon-type enemies. The multiplier is chosen randomly between two values. The chance is roughly 50%. [math]\displaystyle{ \text{Mod}_\text{boss} }[/math][2] Boss (ID) Low mod High mod PT Imp (1637-1640, 2192-2194) 0.4 0.7 BB Hime (1557) 1.7 3.0 Summer BB Hime (1696-1698) 1.5 1.8 CV Hime (1586) 1.7 3.0 CV Hime B (2105-2108) 1.0 1.0 Summer CV Demon (1751) 1.3? 1.7? Ark Hime (1755-1760) ? ? [math]\displaystyle{ \text{Mod}_\text{balloon} }[/math] being the effect of the deployed Barrage Balloons on both side: Balloon Effects 1 2 3 Allied LBAS Damage Allied balloons [3] 1.02 1.04 1.06 Enemy balloons [4] 0.95 0.90 0.85 [math]\displaystyle{ \text{Mod}_\text{crit} }[/math] the critical multiplier of 1.5, It includes the proficiency critical damage multiplier (1.2 for maxed proficiency ❱❱ planes), [5]

Anti-Installation
Pre-cap	[math]\displaystyle{ \text{Atk}_\text{pre-cap} = \bigg\lfloor \text{Mod}_\text{type} \times \Big( \big( {\color{tomato}\text{Mod}_\text{SpInst1}} \times \text{TP/DB} + \bigstar \big) \times \sqrt{1.8 \times \text{Plane}_\text{Count}} + 25 \Big) \times \text{Mod}_\text{Sp3} \times \text{Mod}_\text{LBR} \bigg\rfloor }[/math] With [math]\displaystyle{ \text{TP/DB} }[/math] the: Torpedo stat for Torpedo Bombers (behavior is still unclear). Dive bombing stat for bomber LB Bombers, Dive Bombers, Jets (behavior is still unclear), BomberSeaplane Bombers, and Hayabusa ASW Hayabusa . [math]\displaystyle{ {\color{tomato}\text{Mod}_\text{SpInst1}} }[/math] is 1.1 for the Type 4 Heavy Bomber Hiryuu (Skilled) + No.1 Model 1A Guided Missile and 1 for every other planes.
Post-cap	[math]\displaystyle{ \text{Atk}_\text{post-cap} = \biggl\lfloor \text{Atk}_\text{cap} \biggr\rfloor \times \text{Mod}_\text{Contact} \times \text{Mod}_\text{LBB} \times \text{Mod}_\text{CF} \times \text{Mod}_\text{historical} \times \text{Mod}_\text{balloon} \times {\color{tomato}\text{Mod}_\text{Inst}} \times_\downarrow \text{Mod}_\text{crit} }[/math] Other variables are the same as for anti-ship. [math]\displaystyle{ {\color{tomato}\text{Mod}_\text{Inst}} }[/math] is the anti-installation bonus, the multiplier is chosen randomly between two values. The chance is roughly 50%. see here for more details: [math]\displaystyle{ {\color{tomato}\text{Mod}_\text{Inst}} }[/math][6] Installation (ID) Airstrike LBAS Low mod High mod Low mod High mod Artillery Imp (1665-1667) 1.1? 1.7? 1.6 2.5 Pillbox Imp (2178,2179,2196,2197) 1.2? 1.6? 1.5 2.2 Anti-Air Guns Imp (2180,2181) 1.3 1.6 Pillbox Princess (2188-2191) 1.5 1.9 1.4 1.8 "Old" Supply Depot Princesses (1653-1658) 1.5 2.4 1.7 3.5 "New" Supply Depot Princesses (B, C, D, ...) (ID>1658) Harbour Summer/Holiday Princess (1699-1704,2023-2028,2243-2245) 1.2 1.4 1.2 1.5 Isolated Island Princess (1671-1672) 1.5? 2.0

ASW
Pre-cap	[math]\displaystyle{ \text{Atk}_\text{pre-cap} = \Big\lfloor \left( \big( \text{ASW} + \bigstar \big) \times \sqrt{1.8 \times \text{Plane Count}} + 25 \right) \times \text{Mod}_\text{ASW} \times \text{Mod}_\text{LBR} \Big\rfloor }[/math] With [math]\displaystyle{ \text{ASW} }[/math] the ASW stat of the plane. [math]\displaystyle{ \text{Mod}_\text{ASW} }[/math] a random number based on the base ASW of the plane. It is between: 0.35 and 0.8 for 7-9 ASW planes. 0.7 and 1.0 for 10+ ASW planes.
Post-cap	[math]\displaystyle{ \text{Atk}_\text{post-cap} = \bigg\lfloor\text{Atk}_\text{cap} \times \text{Mod}_\text{crit} \times \text{Mod}_\text{proficiency} \bigg\rfloor \times \text{Mod}_\text{Contact} \times \text{Mod}_\text{LBB} }[/math] Other variables are the same as for anti-ship.
Note Only "ASW Planes" (7+ ASW) are able to perform ASW attacks. If no aircraft in the base can perform ASW attacks, the base will not show at submarine-only nodes.

Notes

• Unlike carrier airstrikes, the 1.2x critical proficiency bonus applies to each slot independently.
• Jet Assault use the airstrike formula even on land base.

Attack Power Corrections

After calculating the basic attack power of the attack being made, it is then adjusted based on various factors. Attack power modifiers can be split into pre- and post-cap modifiers. Post-cap modifiers are more powerful to have because they aren't reduced by the cap.

Pre-cap Modifiers

Engagement

For more information on this topic, see Engagement.

Form	Common name	Damage Modifier	Chance	Chance with Saiun
Crossing the T (Advantage) T字戦有利 (T Ji-sen Yuuri, T字戦有利?)	Green T	1.2	15%	15%
Parallel Engagement 同航戦 (Doukousen, 同航戦?)	Parallel	1.0	45%	45%
Head-on Engagement 反航戦 (Hankousen, 反航戦?)	Head-on	0.8	30%	40%
Crossing the T (Disadvantage) T字戦不利 (T Ji-sen Furi, T字戦不利?)	Red T	0.6	10%	0%

• Engagement modifier affects the Shelling Phase, as well as the Battle Openings, the Closing Torpedo Salvo, and Support Expeditions.
  • All engagement forms affect both sides equally, including Green T and Red T.
  • The exception are ASW and some Special Attacks.
• Night Battle and Aerial Combat are not affected by engagement.

Formation

For more information on this topic, see Formation.

Formation Attack Power Modifiers
Formation	Shelling	Torpedo	ASW	Night Battle
Line Ahead	1.0	1.0	0.6	1.0
Double Line	0.8	0.8	0.8	1.0
Diamond	0.7	0.7	1.2	1.0
Echelon	0.75	0.6	1.1	1.0
Line Abreast	0.6	0.6	1.3	1.0
Vanguard	0.5	1.0	1.0	0.5
	1.0	1.0	0.6	1.0

Combined Fleets have special formations that differ from the standard single fleet formations. The following formations can be selected.

Formation	Formation Icon	Fleet	Shelling	Torpedo	ASW	Night	Notes
Cruising Formation 1 (ASW Alert) 第一警戒航行序列（対潜警戒）		Main	0.8	-	1.3	-	Moderate shelling and torpedo accuracy. Similar to Line Abreast.
		Escort	0.8	0.7	1.3	?
Cruising Formation 2 (Forward Alert) 第二警戒航行序列（前方警戒）		Main	1.0	-	1.1	-	Higher shelling and torpedo accuracy than Formation 1. Similar to Double Line without the accuracy bonus.
		Escort	1.0	0.9	1.1	?
Cruising Formation 3 (Ring Formation) 第三警戒航行序列（輪形陣）		Main	0.7	-	1.0	-	Requires 5 or more ships in the 2nd fleet. Very low shelling and torpedo accuracy. Similar to Diamond.
		Escort	0.7	0.6	1.0	?
Cruising Formation 4 (Battle Formation) 第四警戒航行序列（戦闘隊形）		Main	1.1	-	0.7	-	Requires 4 or more ships in the 2nd fleet. Highest shelling and torpedo accuracy. Similar to Line Ahead.
		Escort	1.1	1.0	0.7	?

The following tab resume when engagement and formation are effective:

Modifier	LBAS	Airstrike	Support			Shelling		Torpedo	ASW	Night Battle
			Shelling	Aerial	Torpedo	Surface	Carrier
Engagement	❌	✔️	✔️	❌	✔️	✔️	✔️	✔️	❌	❌*
Formation	❌	❌	✔️	❌	✔️	✔️	✔️	✔️	✔️	✔️

Note

• If one of the fleet si a combined one then the formation modifier become 1 for the support.

Damage State

Damage State	Shelling	Torpedo	ASW
Not Damaged	1.0	1.0	1.0
Lightly Damaged (小破)
Moderately Damaged (中破)	0.7	0.8	0.7
Heavily Damaged (大破)	0.4	0	0.4

Notes

• Damage state does not affect aerial combat.
  • It will affect carrier attacks in the shelling phase.

Night Battle Cut-In

For more information on this topic, see Night Cut-In.

Night Cut-Ins will apply extra modifiers if triggered.

[math]\displaystyle{ \text{Mod}_\text{CI} }[/math] "New" Cut-ins Attack Type Prerequisites Notes Damage Modifier Destroyer Cut-ins Surface 1.3 With 12.7cm Mod D K2 1.625 With 12.7cm Mod D K3 1.706 With 2 12.7cm Mod D K2 1.820 With both 12.7cm Mod D K2 & K3 1.911 With 2 12.7cm Mod D K3 2.002 Surface 1.2 With 12.7cm Mod D K2 1.5 With 12.7cm Mod D K3 1.575 With 2 12.7cm Mod D K2 1.680 With both 12.7cm Mod D K2 & K3 1.768 With 2 12.7cm Mod D K3 1.848? Requires TSLO 1.5 Requires TSLO 1.3 Carrier Cut-ins = 1.25 1.2 OR 1.2 1.18 Night Zuiun Cut-ins Surface - 1.36 1.32 Surface 1.28 1.24

[math]\displaystyle{ \text{Mod}_\text{CI} }[/math] "Old" Cut-ins Attack Type Prerequisites Accuracy Modifier Gun Cut-in 2 Mixed Gun Cut-in 1.75 Submarine Cut-ins Sub_LM 1.75 Sub_LM Sub_LM 1.6 Torpedo Cut-in 1.5 Mixed Torpedo Cut-in 1.3 Double Attack 1.2

ASW Synergy

ASW Damage Synergy
Small Small Sonars	Type 93 Passive Sonar Type 4 Passive Sonar Type 3 Active Sonar Type 3 Active Sonar Kai Type124 ASDIC Type144/147 ASDIC HF/DF + Type144/147 ASDIC
Large Large Sonars	Type 0 Passive Sonar
DCP Depth Charge Projectors (DCP)	Type 94 Depth Charge Projector Type 3 Depth Charge Projector Type 3 Depth Charge Projector (Concentrated Deployment) Prototype 15cm 9-tube ASW Rocket Launcher RUR-4A Weapon Alpha Kai AP Mk.32 ASW Torpedo (Mk.2 Thrower) AP
DCR Depth Charge (Racks) (DCR)	Type 95 Depth Charge AP Type 2 Depth Charge AP Lightweight ASW Torpedo (Initial Test Model) AP Hedgehog (Initial Model) AP Type 2 Depth Charge Kai Ni AP
Other ASW Mortars	Type 2 12cm Mortar Kai Type 2 12cm Mortar Kai (Concentrated Deployment)
ASW Damage Modifiers: [math]\displaystyle{ \text{Mod}_\text{synergy} = {Mod}_\text{1} \times {Mod}_\text{2} }[/math]
[math]\displaystyle{ {Mod}_\text{1} }[/math]	+ (Any Sonar + Any Depth Charge)	1.15
[math]\displaystyle{ {Mod}_\text{2} }[/math]	DCP + DCR and NO Small	1.1
	Small + DCP + DCR	1.25
Examples
[math]\displaystyle{ \text{Mod}_\text{synergy} }[/math]	Small + DCP + DCR	1.4375[math]\displaystyle{ 1.15 \times 1.25 }[/math]
	Large + DCP + DCR	1.265[math]\displaystyle{ 1.15 \times 1.1 }[/math]
Armor Penetration
Indepentant of synergies, some equipment provides additional armor penetration to ASW attacks. The affected equipment are: DCR: Type 95 DC, Type 2 DC, Lightweight ASW Torpedo, Hedgehog, Type 2 DC K2 DCP: RUR-4A Weapon Alpha Kai, Mk.32 ASW Torpedo (Mk.2 Thrower). The flat armor penetration value is calculated as follows: [math]\displaystyle{ \text{Pen} = \sum\limits_{\text{Equipment}} \Big( \sqrt{\text{ASW}_\text{Equipment} - 2} + \text{Mod}_\text{ship} \Big) }[/math] With [math]\displaystyle{ \text{ASW}_\text{Equipment} }[/math] the base ASW stat of the applicable equipment, Visible Bonuses and Improvements are not counted here. [math]\displaystyle{ \text{Mod}_\text{ship} }[/math] being 1 for DE, 0 otherwise, Note Armor penetration from equipment stacks, The final armor of the targetted submarine cannot go below 1.

Hidden Fit Bonuses

For more information on this topic, see Hidden Fit Bonuses.

Unlike the other pre-cap bonuses, this is just a minor additive firepower bonus added for some ships (mostly cruisers) when equipped with certain guns.

Post-cap Modifiers

Aerial Contact

For more information on this topic, see Aerial Combat#Contact.

During aerial combat, there is a chance for the ships to trigger Contact. When it is triggered, the is a bonus multiplier applied to airstrike damage depending on the Accuracy of the plane that triggered contact.

Accuracy	Damage Modifier
0	1.12
1	1.12
2	1.17
3+	1.2

Airstrike Special Bonus

There's a bonus when attacking certain Princess and Demon-type enemies during airstrike. The multiplier is chosen randomly between two values. The chance is roughly 50%.

[math]\displaystyle{ \text{Mod}_\text{boss} }[/math]
Boss (ID)	Low mod	High mod
PT Imp (1637-1640)	0.5	0.8
BB Hime (1557)	1.4?	2.2?
Summer BB Hime (1696-1698)	?	?
CV Hime (1586)	1.7?	2.2?
CV Hime B (2105-2108)	1.7?	2.2?

Artillery Spotting

For more information on this topic, see Combat/Artillery Spotting.

Attack Type	Prerequisites	Post-cap Damage Modifier	Notes
Main Zuiun Cut-in (Zuiun CI)		1.35	Ise-class Kai Ni only
Main Suisei Cut-in (Suisei CI)		1.3
Main AP Shell Cut-in (APCI)		1.5
Secondary AP Shell Cut-in (Sec APCI)		1.3
Secondary Radar Cut-in (Radar CI)		1.2
Secondary Cut-in (Sec CI)		1.1
Double Attack (DA)		1.2

Carrier Cut-In Attacks

For more information on this topic, see CVCI.

Attack Type	Prerequisites	Post-cap Damage Modifier
Fighter-Bomber-Attacker (FBA)		1.25
Bomber-Bomber-Attacker (BBA)		1.2
Bomber-Attacker (BA)		1.15

If a CVCI attack is evaded, it will deal Scratch Damage instead.

Armor-Piercing Modifier

During day combat, certain enemy ships take extra damage from AP Shells

.

• The bonus only applies against FBB, BB, BBV, CV, CVB, CA, and CAV.
  • This includes Installations.
  • This means that this bonus does not apply against all other types, namely CVL, CL(T), CT, DD, DE, SS(V), AV, AS, AR, LHA, or AP.

Type	Modifier
	1.08
	1.10
	1.15
	1.15

Note

• It is unadvisable to run any of the other setups beyond the most basic Gun+AP, as the other setups will interfere with artillery spotting and give worse bonuses.
• This modifier doesn't affect support shelling.

Anti-Installation Equipment Modifiers

For more information on this topic, see Anti-Installation.

Special Attack Bonus

For more information on this topic, see Special Attacks.

Criticals

For more details on how critical chance is calculated, please see Critical.

Normal Criticals

Attack Type	Modifier
Normal	1.0
Critical	[math]\displaystyle{ 1.5 \times \text{Mod}_\text{proficiency} }[/math]

Plane Proficiency Critical Modifier

For more information on this topic, see Plane Proficiency.

Ammunition Modifier

The damage of the fleet is reduced once their ammunition falls below 50%. This modifier cannot go above 1. The formula used to determine this is:

[math]\displaystyle{ \text{Ammo} }[/math] formula
[math]\displaystyle{ \text{Ammo} = \dfrac{\Big\lfloor \dfrac{\text{Current Ammo} }{\text{Max Ammo} } \times 100 \Big\rfloor}{50} }[/math] With [math]\displaystyle{ \text{Current Ammo} }[/math] the current ammo of the ship. [math]\displaystyle{ \text{Max Ammo} }[/math] the max ammo of the ship (indicated under consuption on the ship info).

Remaining Ammo	Ammo Modifier	Notes
>50%	1.0
40~49%	0.8	4th Battle
30~39%	0.6
20~29%	0.4	5th Battle
10-19%	0.2
0%	0	6th Battle

• The battle number indicated in the notes assumes only normal surface engagements. Engaging in night battles and other special engagements can change that number.
• Whatever ammunition modifier applies in day battle carries over to night battle.
• Maelstroms that reduce ammunition also count towards this modifier.
• Using Underway Replenishment is a way to medigate ammo penalties.
• The ammunition modifier affects aerial battle.
• Once a ship hits 0% ammo, all attacks become scratch damage.
• Debuffs are affected by the ammunition modifier.

Miscellaneous Damage Modifiers

Scratch Damage

In the following cases, attacks will deal "scratch damage" instead of normal ones:

• If a Cut-in or a special attack is evaded;
• The target's armor cannot be penetrated (attack inferior to eh enemy defense);
• The ammo count hits 0;
• When a single fleet attack submarine at night;
• When a Friendly Fleet attacks the last remaining ship of an enemy fleet.

Scratch damage is dealt as a percentage of remaining HP calculated using the following formula:

Scratch Damage formula
[math]\displaystyle{ \text{Damage}_\text{scratch} = \text{HP}_\text{current} \times 0.06 + \text{HP}_\text{rand} \times 0.08 }[/math] With [math]\displaystyle{ \text{HP}_\text{current} }[/math] the current HP of the target. [math]\displaystyle{ \text{HP}_\text{rand} }[/math] a random HP number between 0 and [math]\displaystyle{ \text{HP}_\text{current} - 1 }[/math] Therefore the maximum possible scratch damage [math]\displaystyle{ \text{HP}_\text{current} \times 0.14 - 0.08 }[/math] and the minimum damage is [math]\displaystyle{ \text{HP}_\text{current} \times 0.06 }[/math]. If the target's HP is low, it is possible for the result of the formula to return a result of 0. Remember that all formulas are rounded down. This means the target's HP cannot be reduced to 0 by scratch damage.
Friendly Fleet A Friendly Fleet cannot kill the last ship of the opposing fleet, dealing special scratch damage instead. [math]\displaystyle{ \text{Damage}_\text{scratch} = \text{HP}_\text{current} \times 0.5 }[/math]

• Scratch damage is generally between 6-14% of current HP.

The target's HP cannot be reduced to 0 (and therefore sunk) by scratch damage.

Historical Bonus

On almost every Event map, as well as some regular maps (7-4 & 7-5 so far), certain ships, types of ships, equipment, or types of equipment will bring bonuses.

• Those bonuses are most of the time raw damage multipliers, and sometimes, accuracy bonuses.
• Bonuses are independent to each ship, so only the ships with any historical bonus or ships equipped with historical equipment will be affected.
• Bonuses may be applicable to some parts of a map only, such as specific phases of nodes.

This mechanic is here to encourage the use of "historically significant fleets and setups".

• By nature, historical bonuses are arbitrary, so refer to each individual map to see what bonuses are applicable.

Debuffs

Debuffs are a special case that only applies during events. Certain event maps have debuff mechanics that require meeting certain conditions to trigger them. Debuffs can be either a reduction to the enemy's armor or a post-cap damage modifier for the fleet.

Notes:

• Debuffs are affected by the remaining ammo modifier.

Overkill Protection

When a ship in the fleet takes more damage than her current HP, she will take a percentage of her current HP in damage instead.

• The ship must be the flagship OR
• The ship must not be heavily damaged (大破) nor red morale at the start of the battle.
  • If the ship has red morale, she will just have her HP reduced to 1.

Overkill formula
[math]\displaystyle{ \text{Damage}_\text{Overkill} = \text{HP}_\text{current} \times 0.5 + \text{HP}_\text{rand} \times 0.3 }[/math] With [math]\displaystyle{ \text{HP}_\text{current} }[/math] is the current HP of the ship. [math]\displaystyle{ \text{HP}_\text{rand} }[/math] is a random HP number between 0 and [math]\displaystyle{ \text{HP}_\text{current} - 1 }[/math]
Notes Therefore, the maximum damage from overkill protection is [math]\displaystyle{ \text{HP}_\text{current} \times 0.8 - 0.3 }[/math] and the minimum damage is [math]\displaystyle{ \text{HP}_\text{current} \times 0.5 }[/math].

Overkill protection will take off between 50-80% of the ship's current HP .

Important Information

• In general:
  • Overkill protection is most applicable to DDs.
    • The most pronounced effects of overkill protection occur at low HP
    • It is also the primary means of surviving a hit they fail to evade
    • For example, a 32HP DD has a 15.5% chance of being heavily damaged (大破) by a BB Hime, while a 31 HP DD has just a 6.5% chance
    • This has great implications when marrying ships, 36 HP has one of the highest chances of a taiha
  • Odd-numbered HP is better when overkill protection is triggered. This is because the damage calculations round down, reducing the likelihood of being knocked down to heavy damage.
  • This mechanism is most applicable to ships at full HP. Once a ship starts taking damage, the utility of overkill protection diminishes
• Generally ships with HP that are divisible by 4 have worse survivability.