How to Change Individual Unit Icons in Hearts of Iron IV

Hearts of Iron IV gives modders and players a surprising amount of control over the visual presentation of their armies — including the small but meaningful unit icons that appear on the map and in division templates. Changing these icons is entirely doable, but the process involves navigating Paradox's file structure, understanding how the game reads graphic assets, and knowing which files to edit without breaking anything.

What Are Unit Icons in HoI4?

In Hearts of Iron IV, unit icons (sometimes called division icons or unit sprites) are the small visual identifiers attached to division templates. They appear on the strategic map, in the army interface, and during combat. Each division template can be assigned a specific icon that reflects its composition — infantry, armor, marines, and so on.

These icons are distinct from the 3D unit models you see when zooming into the map. They're flat 2D sprites pulled from specific sprite sheets and defined in the game's interface and graphics definition files.

Where HoI4 Stores Unit Icon Files

The icon assets live inside the game's core installation directory. The relevant folders are:

• Hearts of Iron IV/gfx/interface/ — contains many of the 2D UI sprites
• Hearts of Iron IV/gfx/unit_leaders/ — leader portraits (not division icons)
• Hearts of Iron IV/interface/ — .gfx definition files that tell the game what to call each sprite

Division template icons specifically are referenced through .gfx files and linked to image assets, typically in .dds or .png format. The game uses DirectX DDS files natively, but many modders work in PNG and convert as needed.

How the Icon Assignment System Works

HoI4 doesn't let you simply drag and drop a new image onto a division template from within the game UI. The process works through a definition-and-reference chain:

1. An image file exists in the gfx/ directory
2. A .gfx file in the interface/ folder defines that image as a named sprite
3. The game's division template logic or country-specific files reference that sprite name
4. The template displays the referenced icon in-game

This means changing an icon requires touching at least two files: the image asset itself and the sprite definition that names it.

Step-by-Step: Changing a Unit Icon via Mod 🛠️

Editing base game files directly is never recommended — updates will overwrite your changes. The correct approach is creating or editing a mod.

1. Set Up Your Mod Folder

Use the HoI4 launcher to create a new mod, or navigate to: Documents/Paradox Interactive/Hearts of Iron IV/mod/

Your mod needs a descriptor file and a matching folder structure that mirrors the base game.

2. Locate the Original Sprite Definition

Open the base game's interface/ folder and search .gfx files for the icon you want to replace. You're looking for entries like:

spriteType = { name = "GFX_unit_tag_INF" texturefile = "gfx/interface/unit_icons/infantry.dds" } 

The name value is the sprite key — this is what the game uses internally to display the icon.

3. Create Your Replacement Image

Design or source your new icon image. Key considerations:

• Format:.dds (preferred) or .png
• Size: Match the original's pixel dimensions — mismatched sizes cause display issues
• Transparency: Use alpha channels correctly; HoI4 renders icons against dynamic backgrounds

Place your image inside your mod's mirrored gfx/ path.

4. Override the Sprite Definition

In your mod's interface/ folder, create a .gfx file that redefines the same sprite name pointing to your new image file. The game will load your mod's definition and override the base game's version.

5. Assign Icons to Specific Templates (Optional)

If you want individual templates — not all divisions of a type — to use different icons, this gets more involved. You'll need to look at how division templates are defined in history/ or common/units/ files and whether country-specific overrides or scripted GUIs are involved. Some modders use scripted GUI elements to create more granular icon control.

Variables That Affect the Process 🎮

No two modding situations are identical. Several factors shape how straightforward this process will be:

Common Mistakes to Avoid

• Editing base game files directly — always mod instead
• Wrong image dimensions — the icon will stretch, crop, or display incorrectly
• Duplicate sprite names — two mods defining the same sprite name will conflict unpredictably
• Forgetting the mod descriptor — your mod won't load properly without a correctly formatted .mod file
• Using .png without checking game compatibility settings — some HoI4 versions handle PNG inconsistently in certain contexts

The Spectrum of Icon Customization

At the simpler end, you can swap one icon image for another with minimal file editing. At the more complex end, modders build entire custom icon sets tied to specific nations, ideologies, or unit compositions — dynamically assigned through scripted interfaces.

Whether you're making a light reskin or building a detailed order-of-battle mod with historically accurate unit symbols, the underlying mechanic is the same. What changes is how many files you touch, how carefully you manage conflicts, and how deeply you want the icon logic to integrate with gameplay systems.

Your own path through this depends heavily on what you're trying to achieve, how many templates you want to customize, and whether your mod needs to coexist with others in a player's load order.