Understanding Supply

Seem to always be out of supply? Here's how supplies and logistics works...

Introduction

Supply is a very important thing to consider when commanding and controlling your armies, navies, and air forces in Hearts of Iron IV. While different from equipment, supplies work similarly.

Supply View Mode

View your current supply conditions by clicking on the jerry can icon, as indicated below. It is located at the bottom right corner of the interface.

Note that the supply details are invisible when zoomed out, so it may be necessary to zoom in to view current supply.

Alternatively, use the F4 hotkey.

Supply Penalties

Fleets, wings, and divisions that are out of supply will receive large amounts of attrition, meaning their equipment begins breaking down. Divisions without equipment will fight at considerably less strength.

They also receive penalties to Organization. Since 99% of all battles are won because one side ran out of organization, this can be devastating. Furthermore, the recovery rate of organization falls considerably as well, making it even harder for your units to fight.

Finally, even if they do manage to fight with reduced equipment and organization, they receive a combat modifier penalty which flatly reduces the unit's fighting capabilities.

However, supply penalties scale with severity, and so a division that is only slightly out of supply will still be able to fight with only minor penalties. The penalties listed on the wiki[www.hoi4wiki.com] are the maximum stated, and not necessarily the penalties applied to you at all times when out of supply.

Air Supply

If you have the Waking the Tiger DLC purchased and installed, it is possible to resupply your forces from the air. Doing so costs Command Points, so it is not feasible to maintain for an extended period. Paratroopers and Marines operating behind enemy lines should attempt to capture a port as soon as possible to avoid these out of supply penalties.

Mitigating Out of Supply Penalties

If you expect to send forces into areas where they cannot receive supplies, there are a few things you can do to help curb supply use:

• Generals with the Commando trait will half their regular out of supply penalties. Generals can gain this trait by leading amphibious or paratrooper attacks, or by operating in regions where the temperature is -10° (which will also help unlock Winter Specialist).
  
  
• Field Marshals with the Logistics Wizard trait will receive a 20% bonus to their out of supply penalties instead of a General's 50%. It can be obtained by commanding armies that are out of supply.
  
  
• Logistics Battalions are support battalions that can be attached to your divisions. They will help reduce their supply footprint - reducing the supply penalties by having the division require less in the first place.

Supply Usage

Each airplane, ship, and division uses supply. You can find out how much each unit uses by opening its details.

Divisions

Open the Division Editor, and then click on any Division's Edit button (highlighted in red, top). You can then see its supply usage in the stats window.

Ships

With a single fleet selected, click on an individual ship's icon to bring up its stats screen.

Planes

With a single air wing selected, click on the aircraft's portrait, located just below its name.

Available Supply

Available supply, or supported supply, is the amount of supply that is in each zone. Each division, plane, or ship uses a certain amount of this available supply, and out of supply penalties will begin to accumulate if the available supply is less than the supply demanded by the units in it.

Supported supply is equal to the amount of local supply (supply generated by the province itself) plus incoming supply (supply shipped from elsewhere).

Local supply

Local supply is generated by the province itself. Naturally, units will prefer to use local supply first before attempting to use incoming supply.

Local supply is determined by two factors:

• The "naturally occurring" supply generated by the territory ("Local supply base"). This number is static and cannot be altered through normal means.
  
  
• Victory points provide even more supply, though these also cannot be altered. Capital cities provide the most supply, so basing a division in Moscow, Ottawa, Berlin, or Washington DC is easier than basing a division in Bangor, USA.

Incoming Supply

In an overwhelming majority of cases, you'll want even more supply than is provided by local supply. This is especially true in tiny island bases, where the local supply is pitifully small.

There are two key places to look when determining what your incoming supply is.


In this case, the incoming supply is limited by the current infrastructure (18 points of supply). The naval base in this area is capable of supporting 30, but the low infrastructure is the current bottleneck.

Clicking on the infrastructure icon (left) or the naval base icon (right) will automatically queue a level for your civilian factories to construct. In the above example, civilian factories have already been queued to bring the level 3 infrastructure up to level 10.

For further details on incoming supply, view this part of the tooltip.



As mentioned previously, the incoming supply is 18 because 18 is the maximum amount supported by the infrastructure. This is indicated by the red number in the screenshot. If supplies are being transferred by land instead, the limit may be because of a bottleneck earlier in the chain.

For example, Sector A, your capital, supports 100 supply, and Sector C, containing your army, also supports 100 supply. Sector B, however, can only support 5 supply due to infrastructure damage or a low leveled naval base. As a result of a bottleneck, your army will be out of supply even though the area they are currently in has a large infrastructure.

Extraneous Information - Math Alert
Specifically, the incoming supply over a land route is 0.5 times the square of the average infrastructure in the sending supply area (unless the sector is a capital) plus 2 times the square of the average infrastructure in the receiving supply area. So the above example has exaggerated a potential supply issue supplies will rarely, if ever, run at those exact numbers.

Summary

Have other questions? See the RTS Gamer's Guide to Hearts of Iron 4

Appendix - Sources

• Hearts of Iron IV Wiki - Logistics[www.hoi4wiki.com]
  
  
• Hearts of Iron IV forum thread[forum.paradoxplaza.com]

[VladVeganu]

Update for new no step back system?

[Blackbeard_teach]

so, i have a region that i need to fight in, however all the troops have supply issue, what is the most effecient way to get them some supply WHILE infastructor is being built.

so far i think transport planes can help with that but i was thinking of using smaller armies for that job

[Justin]

Encirclement or materiel/manpower.

[agznai]

What are 1% of battles win by if it isnt org?

[Justin]

Not entirely sure on that, sorry. You'd probably be better off asking Discord or Reddit or something rather than the comments section of a guide on supply. Then you can post things like screenshots of what you're trying to do.

[[50pc.] bluetarp]

im going at america from eastern canada via greenland via england and my troops in newfoundland simply cannot get off thier knees due to low supply. my nearby naval bases are at 10, the supply lines are all protected 24/7, infrastructure at max, and i simply cannot do shit. endless waiting for supply. what to do?? the units arent even that big.

[Justin]

Many thanks for the kind words, crew.

[GalloRojo]

Justin, you open my eyes, thanks a lot, the best explanation about supply!!!

[TheAltoonaWiseman]

@ Viri- Couldnt have said it Better!

[koyaan]

Hey, I think I could invade Poland without getting annexed by Poland now! Or maybe even Czechoslovakia! ( I am bad at this game.)