Improvements are upgrades to equipment that increase their performance or upgrade them to better versions. Improvements are done in Akashi's Improvement Arsenal, requiring Akashi. Improvement Materials are notably used for improvements.

For a comprehensive list of improvements, please refer to Akashi-List or the List of Improvements.

Overview

Improvement levels are displayed beside equipment names.
- They run from +1 to (+10).
Improvement bonuses are hidden. The increase in stats is not reflected on ship girls' stat cards.
- This means they do not count for Support Expeditions or for reaching certain thresholds like for OASW.
- Those bonuses work to some extent to reach regular Expeditions thresholds.
- Some improvements on equipment can add some additional visible Fit Bonuses.
Equipped equipment cannot be improved.
- There is an option to unequip the equipment from the improvement list.
Equipment must be unlocked in order to be upgraded to a better version.
Improvements have a chance to fail. Please see below.
- Materials and any fodder equipment are still lost on failure.
  - Items are not lost.
- The equipment being improved is never lost.
- It is recommended to use the guaranteed improvement toggle when dealing with expensive improvements and/or rare fodder at +6 and beyond.
- Akashi Kai has a higher success rate than her base version.
Improved equipment cannot be used as fodder.
Certain conversion quests like F13, F14, F15, F19, F22, and F24 to F30, that do not require improved equipment, will carry over any to the upgraded equipment.
- This is currently the only way to obtain improved versions of the Tenzan Model 12 (Tomonaga Squadron), Suisei (Egusa Squadron) & Reppuu (601 Air Group) (unimprovable otherwise).
Certain conversion quests like F62, F89, F70, and F107, allow to use Improved equipment, but any are lost during conversion.

Improvement Success Rates

Akashi's level does not affect improvement rates. However, her remodel status does. It is highly recommended that she be remodeled to Kai as soon as possible, to maximize improvement success rates. The data below is sourced from KanColle Kai.

Modification Level	1★	2★	3★	4★	5★	6★	7★	8★	9★	Max★	Upgrade
Akashi	100%	100%	100%	100%	95%	90%	80%	77%	72%	60%	50%
Akashi Kai	100%	100%	100%	100%	100%	95%	90%	82%	77%	67%	62%

Improvement Bonuses

The bonus stats gained from improvement will vary depending on the type of equipment as well as the stat itself.

Most improved stats will come as decimal numbers due to the use as base decimals and how square roots work.
It is important to note that decimals must not be discarded in favor of whole numbers, as stats will be multiplied by various formulas anyway, to finally be rounded down/up.
For calculated improvment bonuses, please refer to the Reference Charts.

Rations

are the only equipment that do not gain any stats from improvement.

Improvement only serves to upgrade them into their improved versions.
Since improving a Combat Ration up to +6★ cost 0 screw, it is possible to farm some screw by upgrading a ration once a day while doing quest F18.

The improvement effects are unknown for LB Land-based Recons
and Command Facilities

.

Square Rooted Bonus

Most bonuses are all a function of the square root of the improvement level. The bonus can be calculated by:

[math]\displaystyle{ \text{Bonus}_\text{stat} = \sum_{\text{All equips}} \text{Mod}_\text{equip} \sqrt{\bigstar} }[/math]

[math]\displaystyle{ \bigstar }[/math] is the improvement level of the equipment.
[math]\displaystyle{ \text{Mod}_\text{equip} }[/math] is the equipment modifier for that stat. Please refer to the table below for details.

Equipment Type			Day Battle		Night Battle	ASW	AA		LoS	Accuracy		Evasion		CI rates
Equipment Type			Firepower	Torpedo	Night Battle	ASW	Equipment AA	Fleet AA	LoS	Shelling	Torpedo	Shelling	Torpedo	Fleet	Enemy
Main Guns	Small Guns (Red)		1	-	1	-	-	-	-	1	-	-	-	-	-
	Main High-Angle Guns (Green)		1	-	1	-	0.7	2^[1] 3^[2]	-	1	-	-	-	-	-
	Medium Guns (Red)		1	-	1	-	-	-	-	1	-	-	-	-	-
	Large Guns		1.5	-	1	-	-	-	-	1	-	-	-	-	-
Secondary Guns	Surface (Yellow)		Linear 0.3	-	Linear 0.3	-	-	-	-	1	-	-	-	-	-
	15.2 cm Single & OTO		1	-	1	-	-	-	-	1	-	-	-	-	-
	High-Angle (Green)		Linear 0.2	-	Linear 0.2	-	0.7	2^[3] 3^[4]	-	1	-	-	-	-	-
	90 mm Single HA		1	-	1	-	0.7	3	-	1	-	-	-	-	-
	5" Twin Secondary CD^[5]		Linear 0.3	-	Linear 0.3	-	0.7	3	-	1	-	-	-	-	-
Anti-Air Guns			1	1.2	-	-	0.7	-	-	-	2	-	-	-	-
Anti-Aircraft Fire Directors			1	-	1	-	0.7	2	-	1	-	-	-	-	-
Torpedoess			-	1.2	1	-	-	-	-	-	2	-	-	-	-
Midget Submarines			-	-	1	-	-	-	-	-	-	-	-	-	-
Carrier Recons			-	-	-	-	-	-	1.2	-	-	-	-	-	-
Seaplanes	Reconnaissance		-	-	-	-	-	-	1.2	-	-	-	-	-	-
Seaplanes	Bomber		-	-	-	-	-	-	1.1	-	-	-	-	-	-
Liaison Aircraft			-	-	-	-	-	-	-	1	-	-	-	-	-
Land Based Bombers	Attackers/Assault/Heavy Bombers		-	0.7	-	-	0.5	-	-	-	-	-	-	-	-
	Ginga & Type 1 Nonaka		-	0.7	-	-	Linear 0.25	-	-	-	-	-	-	-	-
	Hayabusa bomber		-	-	-	-	0.5	-	-	-	-	-	-	-	-
Radars	Surface	Large	-	-	-	-	-	-	1.4	1.7	-	-	-	-	-
	Surface	Small	-	-	-	-	-	-	1.25		-	-	-	-	-
	Dual Purpose	Large & Very Large	-	-	-	-	-	1.5	1.4		-	-	-	-	-
	Dual Purpose	Small	-	-	-	-	-		1.25	1	-	-	-	-	-
	Air Radar	Large	-	-	-	-	-		1.4		-	-	-	-	-
	Air Radar	Small	-	-	-	-	-		1.25		-	-	-	-	-
Submarine Radar			-	-	-	-	-	-	-	-	-	-	-	+?%	-
Searchlights			1	-	1	-	-	-	-	-	-	-	-	-	-?%
Depth Charges			0.75	-	-	0.66	-	-	-	-	-	-	-	-	-
Sonars			0.75	-	-	0.66	-	-	-	1.3^[6]	-	-	1.5	-	-
Engines			-	-	-	-	-	-	-	-	-	1.5		-	-
Shells			1	-	1	-	-	-	-	1	-	-	-	-	-
Landing Crafts & Amphibious Tank			1	-	1	-	-	-	-	-	-	-	-	-	-
Anti-Ground Artillery			1	-	1	-	-	-	-	-	-	-	-	-	-
Lookouts			1	-	1	-	-	-	-	-	-	-	-	-	-

↑ For guns with AA ≤ 6
↑ For guns with AA ≥ 7
↑ For guns with AA ≤ 7
↑ For guns with AA ≥ 8
↑ https://twitter.com/hedgehog_hasira/status/1548329561636495373
↑ Applies to ASW only.

Linear Bonus

Some bonuses just have a linear growth. The bonus per improvement level is given by the table below.

Equipment Type		Fighter Power	Dive Bomb	Torpedo	ASW	Armor	Anti-Installation Bonus^[1]	Expedition Bonus^[2]
Submarine Torpedoes		-	-	0.2	-	-	-	-
Carrier-based Planes	Fighters/SPF	0.2	-	-	-	-	-	-
	Fighter-Bombers	0.25	-	-	-	-	-	-
	Dive Bombers (ex. FB)	-	0.2	-	0.2	-	-	-
	Torpedo Bombers	-	-	0.2	0.2	-	-	-
Interceptors		0.2	-	-	-	-	-	-
Armor	Medium	-	-	-	-	0.2	-	-
Armor	Large	-	-	-	-	0.3	-	-
Seaplane Bombers		-	0.2	-	-	-	-	-
Rotorcrafts	Basic	-	-	-	0.2	-	-	-
Rotorcrafts	Advanced	-	-	-	0.3	-	-	-
Liaison Aircraft		-	-	-	0.2	-	-	-
Landing Crafts		-	-	-	-	-	0.02%	0.05%^[3] 0.02%^[4]
Amphibious Tanks		-	-	-	-	-	0.03%	0.01%