How Supply Works in Hearts of Iron IV

With the No Steps Back update, managing supply lines got more complicated to say the least. Instead of just worrying about infrastructure levels and producing enough equipment, now the player has to worry about rail lines, motorization levels, and supply nodes. Worry not however, as I’m here to explain the new supply system in Hearts of Iron IV.

Supply is a representation of everything your army needs to function, such as equipment, fuel, and manpower. Without supply, you will find your divisions have some serious debuffs applied that make it difficult to keep up the fight. It effectively represents your capacity for divisions in a province, and going over it will inevitably lead to problems for you.

The supply network of Germany in 1936 in Hearts of Iron IV.
The supply network of Germany in 1936

Some consequences of not having enough supply include no manpower reinforcements, fuel not reaching your divisions, and your divisions taking attrition.

All supplies originate in the capital of your country, making it vital that you control the capital and the areas around it. From your capital, supplies are distributed locally, with the range depending on the motorization level in the region, and via railways, which require trains to operate. Railways carry supplies to nodes which will directly distribute supplies to your divisions.

A vital part of the new supply system are supply hubs. These serve as depots for your supplies when divisions are nearby, and will keep your divisions ready for combat. The amount of supply available in a hub is dependent on the railway network that the hub is connected to. Higher-level railways will allow for more supply to be held in a hub, and therefore more divisions in a certain area. However, the entire railway between the hub and the capital has to be upgraded to see benefits.

An example of a supply node in Brandenburg in Hearts of Iron IV.
An example supply node

From these hubs, supply will be distributed to your divisions in a certain range around the hub. You can increase the range by improving the motorization level of a hub, at the cost of trucks from your stockpile.

Railways are effectively the backbone of your supply network. They serve as transportation for supplies across your entire country, and require the production of trains to function. While civilian trains will work, you may find it necessary to research different train models to suit your needs.

An example of railways on the map in Hearts of Iron IV.
Railways as seen on the map. They can overlap and go in different directions with no penalty.

If you’re familiar with the phrase “A chain is only as strong as its weakest link,” then you’ll have a good understanding of railway networks. For example, if you have a railway route between a hub and your capital that is level 3 for most of it, but still has a single level 1 railway, then the entire route functions as if it were level 1. Luckily, Hearts of Iron makes the process of upgrading your railways less tedious by adding an “Upgrade bottlenecks” button when hovering over a supply node.

Improving your supply network is a simple process, but it will require significant foresight and industrial capacity to execute it properly. One important tip is to always be producing trucks and trains, as they can be destroyed and your supplies will stop being distributed without them. Besides that, you should make sure there are no bottlenecks to supply hubs around your country. Personally, I upgrade the bottlenecks at each supply node on the edges of my country to ensure adequate supply in the future.

Additionally, upgrading your state infrastructure remains important, so be sure to check infrastructure levels if you are having trouble with supply. Following these tips will leave you in a strong position to focus on war.

With a strong understanding of your supply network, you overcome one of the biggest obstacles to succeeding in Hearts of Iron IV, putting you in a strong position to excel in your next campaign. If you have any questions about the information in this guide, or other questions about supply in HOI4, let me know in the comments below.

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Lucky Boop
Lucky Boop

Strategy game enthusiast, especially Paradox titles and the Civilization series. Whenever he's not writing he spends his time watching sports, enjoying coffee, or studying history.

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