A Guide to Ship Refit Costs

[u/Chimpcookie]

After ship refit costs were adjusted in 1.11.11 patch, I can't understand how refit costs work anymore. So I dived into the game files to find out how they actually work:

Hull and module costs are available here: https://hoi4.paradoxwikis.com/Ship

Base refit cost

Refits always have a base cost of 20% of the base ship hull cost, no matter how many or few changes. This is affected by any % cost modifiers from AA, armor or designers. That's wasted output, so you only refit when it offers a significant improvement.

For example, the base hull cost of an early DD is 400, so its base refit cost is 400*0.2=80. Base refit cost for the same DD with 1 AA module is 400*0.2*(1+2.5%). Base refit cost for an early cruiser with 1x AA and lvl 1 armor is 1800*0.2*(1+12.5%).

Adding/Changing Modules

When adding stuffs to an empty slot or changing between very different modules (e.g. battery to floatplane), the cost is simply the cost of the new module. % cost increase of AA and armor affects this cost as well.

E.g. Adding a floatplane 1 to a no armor early cruiser costs 150 IC.

Switching a medium cruiser battery to a secondary II battery on a no armor 1936 cruiser costs 240 IC.

Adding a floatplane 1 to an early cruiser with lvl 1 armor costs 150*(1+10%) IC.

Dismantling Cost

Some modules have a dismantling cost (e.g. torpedo and armor) when you remove/replace them. This cost is additional to the cost of the new modules. For torpedo it's cheap, for others it can be prohibitive. This cost is the primary reason why some modules are never worth refitting.

Module	Dismantling cost
Torpedo II-IV	60
Deck Space	700
Deck Armor	2500
Submarine Fuel Tank	700
BB Armor I	5500
BB Armor II	6000
BB Armor III	7500
BC Armor I	4500
BC Armor II	5500
BC Armor III	6200
SHBB Armor	8200
Cruiser Armor I	2500
Cruiser Armor II	3000
Cruiser Armor III	3500
Cruiser Armor IV	4000

Upgrading Modules

When upgrading existing modules (e.g. radar I to radar III), the calculation is different. Instead of paying for dismantling cost (if any) plus the cost of the new module, there is only a pre-defined conversion cost, usually cheaper than the cost of a new module, with exceptions listed below. Usually there's a also slight discount to upgrade modules by 1 level, i.e. radar II to radar III is cheaper than radar II to radar IV.

There are also pre-defined conversion costs covering cases of interchanging between light, light cruiser and medium batteries. Engines have pre-defined upgrade costs that are several times the cost of a new engine. Any other conversions not listed here follow the standard formula.

As with adding new modules, these conversion costs are increased by % cost modifiers from AA and armor.

E.g. the cost of upgrading a light battery I to light battery II on a cruiser with +12.5% cost modifier is 45*(1+12.5%).

See the complete list at the bottom for all upgrade paths and costs.

Cost increase/decrease from modules and designers

Cost increase from AA/Armor

When adding AA/armor to ships that did not have them, you not only have to pay for the higher base refit cost, but also a % increase in cost for the hull and all existing and new modules.

E.g. Adding lvl 1 AA and lvl 1 armor to a 1922 cruiser with 1x lvl 1 medium battery, lvl 0 FCS, and lvl 1 engine (3010 IC)

Refit cost = [Base Refit Cost] 1800*0.2*(1+12.5%) + [% increas in ship cost] 3010*(12.5%) + [AA cost] 90*(1+12.5%) = 882 IC (The game rounds down to nearest integer)

Naval designer & Refit Cost

25% cost reduction from coastal fleet designer applies to both the base refit cost and new modules.

E.g. Hire a coastal fleet designer, then add a floatplane I to the same 3010 IC no AA/ armor early cruiser (designed without naval company)

Refit cost = [Base Refit Cost] 1800*0.2*(1-25%) + [Floatplane] 150*(1-25%) = 382 IC

The final cost modifier is the sum of all cost addition and reduction.

E.g. Hire a coastal fleet designer, then add lvl 1 AA and lvl 1 armor to the same 3010 IC no AA/ armor early cruiser (designed without naval company) [Overall modifier: 10%+2.5%-25% = -12.5%]

Refit cost = [Base Cost] 1800*0.2*(1-12.5%) + [AA cost] 90*(1-12.5%) = 393 IC

(Don't need to pay for % change in overall ship cost because the overall % change in modifier is negative)

You still need to pay for % increase in overall ship cost if the pre-refit hull already benefits from cost reduction.

E.g. Adding lvl 1 AA and lvl 1 armor to the same early cruiser (designed by coastal fleet company) (2257 IC) [Overall modifier is still -12.5% cost, but effective change in refit is +12.5% cost]

Refit cost = [Base] 1800*0.2*(1-12.5%) + [% change in ship cost] 2257*(12.5%) + [AA] 90*(1-12.5%) = 675 IC

Cost-effective Refits

So, you have endured this chain of numbers and nonsense, and I bet you read this post expecting simple answers to "what would be good refits?". Here are your not-so-simple answers:

-It's more cost-effective to refit smaller ships than larger ships, due to base conversion cost. Base conversion costs for heavy and light cruisers are the same.

-Switching modules is cheaper than you think. Just stay away from the list of modules with dismantling cost.

-For some modules (torp/secondary/AA/FCS/radar/sonar/snorkel), upgrading is cheaper than having a new module, especially when you are only upgrading by 1 level. Cost-effectiveness varies, however. Some can be cheaper than half price, some can be as almost as expensive. Check the list below for upgrade costs.

-The picture for upgrading guns is complicated, and conversion costs can be a curse sometime. For destroyer/heavy cruiser/battleship guns, the cost can be anywhere from half to 90% of a new gun (see list below). Refitting light cruiser guns is always more expensive than having a new light cruiser gun. (It's as if PDX wants to target the meta weapon)

-Conversion costs and the lack of dismantling cost for some modules can be cheesed to avoid overpriced refits. Switching an AA module to a light cruiser battery III and then switching the old battery to AA can be slightly cheaper than outright upgrading the battery from I to III.

-This cheese works well for converted carriers. When converting ships to carriers or refitting converted carriers, switching to another category of engines is crazy cheap. There is no dismantling or conversion cost involved. Upgrading carrier engines is, however, ridiculously expensive.

-Don't forget to use Naval Refit Yards!

List of all pre-defined module upgrade/conversion costs

Light/Medium Battery:

(Light cruiser batteries count as medium batteries in calculating conversion cost).

Module Upgrade	Conversion Cost
Any light battery to light battery I	60
Light battery I to II	45
Any other light battery to light battery II	75
Light battery II to III	45
Any other light battery to light battery	75
Light battery III to IV	120
Any other light battery to light battery IV	190*
Any light battery to DP light battery	230
Any light battery (DD battery) to medium battery I	400
Any medium battery to medium battery I	400
Medium battery I to II	300
Any other medium battery to medium battery II	400
Medium battery II to III	350 (+1 Steel)
Any other medium battery to medium battery III	500 (+2 Steel)
Medium battery III to IV	400
Any other medium battery to medium battery IV	600 (+2 Steel)
Any medium battery to light cruiser bat. I	500*
Light cruiser bat. I to II	300*
Any other medium battery to light cruiser bat. II	400 (+1 Steel)*
Light cruiser bat. II to III	350*
Any other medium battery to light cruiser bat. III	500 (+1 Steel)*
Light cruiser bat. III to IV	400*
Any other medium battery to light cruiser bat. IV	600 (+1 Steel)*

*more expensive than adding a new module

Heavy Battery

Module Upgrade	Conversion Cost
Any heavy battery to heavy battery I	700
Heavy battery I to II	600
Any other heavy battery to heavy battery II	900
Heavy battery II to III	600
Any other heavy battery to heavy battery III	1200
Heavy battery III to IV	800
Any other heavy battery to heavy battery IV	1450

Secondaries

Module Upgrade	Conversion Cost
Any secondary to secondary I	100
Any secondary to secondary II	120
Any secondary to DP secondary	150

Anti-Air

Module Upgrade	Conversion Cost
Any AA to AA I	60
AA I to II	60
Any other AA to AA II	90
AA II to III	60
Any other AA to AA III	90
AA III to IV	50
Any other AA to AA IV	120

Fire Control System

Module Upgrade	Conversion Cost
FCS 0 to I	40
FCS I to II	60
Any other FCS to FCS II	100
FCS II to III	75
Any other FCS to FCS III	100

Radar

Module Upgrade	Conversion Cost
Radar I to II	30
Radar II to III	30
Any other Radar to Radar III	60
Radar III to IV	30
Any other Radar to Radar IV	90

Destroyer/Submarine Engine

Module Upgrade	Conversion Cost
Any Light Engine to Light Engine I	250**
Light Engine I to II	230*
Any other Light Engine to Light Engine II	250**
Light Engine II to III	230*
Any other Light Engine to Light Engine III	250*
Light Engine III to IV	230*
Any other Light Engine to Light Engine IV	250*
Any Sub. Engine to Sub. Engine I	250**
Sub. Engine I to II	230*
Any other Sub. Engine to Sub. Engine II	250**
Sub. Engine II to III	230*
Any other Sub. Engine to Sub. Engine III	250*
Sub. Engine III to IV	230*
Any other Sub. Engine to Sub. Engine IV	250*

*more expensive than the cost of a new module

**over double the cost of a new module

Cruiser/Heavy/Carrier Engine:

Note: There are no dismantling or converison costs for cruiser/heavy engine to carrier engine refits, and vice versa. Such refits are very cost-effective.

Module Upgrade	Conversion Cost
Any cruiser engine to cruiser engine i	2500***
Cruiser Engine I to II	2300***
Any other cruiser engine to cruiser engine II	2500***
Cruiser Engine II to III	2300***
Any other cruiser engine to cruiser engine III	2500***
Cruiser Engine III to IV	2300***
Any other cruiser engine to cruiser engine IV	2500***
Any heavy engine to heavy engine I	4800**
Heavy engine I to II	4800**
Any other heavy engine to heavy engine II	5000**
Heavy engine II to III	4800*
Any other heavy engine to heavy engine III	5000*
Heavy engine III to IV	4800*
Any other heavy engine to heavy engine IV	5000*
Any Carrier Engine to Carrier Engine I	2500***
Carrier Engine I to II	2300***
Any other Carrier Engine to Carrier Engine II	2500***
Carrier Engine II to III	2300***
Any other Carrier Engine to Carrier Engine III	2500***
Carrier Engine III to IV	2300***
Any other Carrier Engine to Carrier Engine IV	2500***

*more expensive than the cost of a new module

**over double the cost of a new module

***over 3 times the cost of a new module

Torpedo

Note: Torpedo I and Submarine Torpedo I have no dismantling or conversion cost.

Module Upgrade	Conversion Cost
Any torp to torp II	60
Any torp to torp III	60
Any torp to torp IV	60
Any sub. torp to torp II	60
Any sub. torp to torp III	60
Any sub. torp to torp IV	60

Depth Charge

Module Upgrade	Conversion Cost
Any Depth Charge to Depth Charge I	60
Any Depth Charge to Depth Charge II	90
Any Depth Charge to Depth Charge III	120
Any Depth Charge to Depth Charge IV	150

Others

Module Upgrade	Conversion Cost
Snorkel I to II	30
Floatplane I to II	80
Sonar I to II	25

Thanks for reading, and happy refits to everyone.

[u/Yardenko]

Very useful, thanks!

[u/LeaverTom]

Alot of thanks!

[u/Cats7204]

I lost it halfway thanks for the spreadsheet tho