Of all the Paradox titles to deploy massive libraries of user-made addons and modifications, none might compare with the whopping collection of over 20,000 Hearts of Iron 4 mods. Even if you’re a seasoned HOI4 fan, modding this game is a very deep well to dive into without a guide – so here’s ours, profiling the best of the bunch, with installation tips too.
While we all wait patiently for Hearts of Iron 5 to emerge, the wide world of HOI4 mods is a smorgasbord of mechanical tweaks and fiddles to choose from, adding new systems for AI, textures, music and more. These mods do everything from slightly tweaking key in-game variables to transplanting the game into entirely new worlds.
With each of the many HOI4 DLC expansions, the gargantuan family of mods has grown further, with players turning Paradox’s every new addition to their own creative ends while chasing weird and wonderful HOI4 achievements. If you run into any brick walls while trying ’em out, you may find our guides to HOI4 console commands and HOI4 country tags helpful. For a wider variety of game-warping cheat options, try our sister site CodesDb’s massive database of game codes.
With the mission briefing done, let’s ride this tiger, and focus on four salient categories to encircle some of the best HOI4 mods out there.
These are the best Hearts of Iron 4 mods in 2023:
- Cold War Iron Curtain: A World Divided (Total Conversion)
- End of a New Beginning (Total Conversion)
- BlackICE Historical Immersion Mod (Total Conversion/Immersion)
- The Great War (Total Conversion/Immersion)
- The Road to 56 (Total Conversion/Immersion)
- Hearts of Oak – Man the Guns (Total Conversion/Immersion)
- Millennium Dawn: Modern Day Mod (Total Conversion/Immersion)
- Kaiserreich (Alternate History)
- Old World Blues (Alternate History)
- Expert AI 4.0 (Mechanics/Balance)
- Player-Led Peace Conferences (Mechanics/Balance)
- Thicc Cities – Continued (Gameplay/Map)
- HOI4 In Real Time! (Mechanics/Balance/why)
- Country Roulette (Gameplay)
- Soldier’s Radio (Cosmetic)
- HOI4 – Texture Overhaul – Terrain (Cosmetic)
- World News (Cosmetic)
- How to mod Hearts of Iron 4
Cold War Iron Curtain: A World Divided (Total Conversion)
This is a new mod that’s risen in popularity since we last did our checks. As implied by the title, it changes the setting to the Cold War period, with start dates ranging from 1949 through to 1970. There are plans to extend the timeline into the 1990s.
This mod features between 10-20 years worth of content for all the major powers, including some minors. It also has thousands of new events, new units, new mechanics including DECON and MAD. You can purchase equipment from the private sector, a new economic system. Many nations have their own unique mechanics as well. Do read our full HOI4 Cold War Iron Curtain A World Divided review for the whole story on this mod.
Make sure you don’t accidentally download the old version of the mod. You want this one here. Compatible with Collie 1.10.
End of a New Beginning (Total Conversion)
This mod caught our eye recently via our Discord sever, as it appeared to offer a Victorian-era experience wrapped in Hearts of Iron’s shenanigans. We immediately sent our resident HoI 4 mod guru, Timothy, to check it out and answer one simple question: Is End of a New Beginning the Victoria 3 we’ve been looking for?
Short answer, probably not. The mod is still in relatively early days, and there’s only dedicated content up to 1885.
Furthermore, we’re worried its commitment to extending the timeline from 1857 through to 2050 is a bit ambitious, given the vastly different worlds represented in that start and end date. They might as well just ask Paradox to make a new game.
Also, warfare in EoanB isn’t that satisfying as it still uses the mechanics from vanilla HoI 4, more or less. Waging war in the 19th century feels no different than waging war in the 20th, so there’s still plenty of work to be done. That said, this is still a fascinating project, and one to keep an eye on!
Officially compatible up to Patch 1.9.3. Does not require any DLC at the moment, and users are reporting that it seems to work fine with 1.10 Collie anyway.
BlackICE Historical Immersion Mod (Total Conversion/Immersion)
One of the more famous mods from the days of Hearts of Iron 3, BlackICE is an immersion & realism mod aimed at making the game more challenging & historical. It’s actually recommended that you play with ‘Historical Focus’ switched on for this mod, as it caters for the crowd who specifically want the challenge of WW2 as it unfolded, as opposed to the growing alt-history/sandbox crowd.
Everything from new units and equipment, to new national Focus Trees (many borrowed from other mods that have done good work in this area), to expanding on the Law and Politics mechanics has been looked at. The AI is more challenging, there’s more breadth and depth of options, and generally speaking this an excellent historical immersion experience.
BlackICE is compatible with Husky 1.9.3 and there’s a test version for 1.10 Collie currently live here.
The Great War (Total Conversion/Immersion)
Why fight WW2, when you can fight WW1 instead? The Great War does exactly what it says on the tin – Hearts of Iron 4 has been transformed to the world of 1910, where old-fashioned imperialistic powers jockey for supremacy at the dawn of the 20th Century.
The game & mechanics have been completely overhauled to fit the period – that means that innovations like Tanks and Planes will take a while to enter the fray, so you’ll mainly be looking at infantry tactics. The team is currently at work on bridging the gap between the First and Second World Wars, with work being done on the interwar tech and decision trees.
Fun fact, the developers of this mod have actually launched a Patreon to fund development of their from-scratch WW1 game, Fields of History: The Great War.
This mod is compatible with Version 1.10 Collie & all DLC.
The Road to 56 (Total Conversion/Immersion)
More than just extending the timeline to 1956, this mod peppers the entire world with greater detail and complexity. Not content to wait for Paradox to release content packs for various countries, The Road to 56 provides deep and sometimes quirky focus trees for dozens of countries overlooked by the base game.
The most amazing part about this deeper focus on different countries is that it offers choices that go to the very heart of the focus system: the ability to choose a nation’s destiny does not need to be an exercise in strict historicity. The creativity that the team places on the focus trees is bolstered by upgrades and expansions to the technologies, political mechanics, laws, etc. This is a one stop shop for a total enhancement of the game.
This mod is compatible with Version 1.9.2 Husky & all DLC. At the time of writing, an update to 1.10 Collie is expected within the next week.
Hearts of Oak – Man the Guns (Total Conversion/Immersion)
Sometimes totally overhauling the game requires a subtle touch. In this case, Hearts of Oak does not attempt to change the base game into something unrecognizable but enhances and re-balances technologies, industries, wars, events etc. in areas where the Paradox team may have glossed over.
Complete with a much improved AI, playing HOI4 no longer feels like a ‘solved’ game as most playthroughs can – but rather becomes a dynamic and challenging foray into the dangers of global total war. With a keen focus on deepening historical accuracy with challenges for the player, this mod succeeds in bringing more life to this cacophony of death.
This mod is compatible with Version 1.10 Collie & all DLC.
Millennium Dawn: Modern Day Mod (Total Conversion/Immersion)
Winner of the ‘Outstanding Modding Achievement’ at the 2018 PDXCon, Millennium Dawn delivers exactly what one would imagine: the modern world set in stunning detail on the HOI4 Engine.
This mod will be the closest we’ll get to a global geopolitical grand strategy set in contemporary times and its fantastic depth makes it an exciting if not eerie look at today’s world. One of the best examples of the impressive capabilities of totally overhauling the game, this mod promises political intrigue that’s worthy of network news.
Last time we checked, this mod is compatible with Husky 1.9.1. We’re not sure about later versions at this time.
Kaiserreich Mod (Alternate History)
The veteran alternate history mod on the block. This mod can trace its origin back to Hearts of Iron II. Kaiserreich asks the daring question of: “What if Germany won WWI?”. A deeply rich world fourteen years in the making, every aspect of this alternate history is fully fleshed out in this latest incarnation to delight fans of the legacy of this mod as well as new players.
Tackling an entirely dynamic yet strangely parallel political landscape boasting thousands of unique events, fully fleshed out focus trees, and quirky interactions, this mod gives the player a tantalizing taste of living in an alternate timeline. A true joy to experience for the story and drama with brand new ideologies and situations based on all of the consequences of this ‘what if’.
The visual appeal is impressive, as the custom models and graphics add true immersion to this other world. If you’re interested in learning more, we did a more in-depth Kaiserreich mod review that explores what makes it so compelling.
This mod is compatible with Version 1.10 Collie & all DLC. Please note that a new version of the mod has been uploaded under a new entry, and you’ll need to unsubscribe and re-subscribe to the new version.
Old World Blues (Alternate History)
Old World Blues brings the Fallout universe to HoI4, which makes for a surprisingly solid combination. The research tab has been replaced by a new tech tree, reflecting the state of the Fallout universe in 2275; some of the ‘tribal’ factions will be equipped with spears and scavenged firearms, where the more advanced factions can research and deploy the vaunted Power Armor that has been on the cover of most every Fallout release in the last few years.
Many of the factions will have their own unique decisions and focus trees. Much of this will be familiar to players of New Vegas, but there is plenty grabbed from the lore of the first and second Fallout games as well. There is a lot of depth here, and more on the way, as the modding team is looking to expand the map eastward past the plains and to the Atlantic coast, where we will see the Capital Wasteland and the Commonwealth of Boston represented as well. Keep your eye on this one.
This mod is compatible with Version 1.10 Collie & all DLC. There is a legacy version here.
Expert AI 4.0 (Mechanics/Balance)
This could also be considered an ‘overhaul’ mod of sorts given the extensive work done with the AI, but it’s not meant to necessarily give the player an alternative scenario or a more immersive experience.
Expert AI puts in a lot of behind the scenes work to make the AI a more challenging opponent for the players, specifically with the 1936 start with Historical Focus mode turned on. It’s not able to address everything, but it touches a wide range of AI behaviours & decision making systems so that computer opponents fight smarter & harder. It’s also not recommended you use this mod while playing minor nations.
This mod is compatible with Version 1.10 Husky & all DLC, although it has some very specific compatibility requirements. If you don’t have Man the Guns, the mod will also cause some unexpected AI behaviour.
Player-Led Peace Conferences (Mechanics/Balance)
Never to trust the AI to have our best interests at heart, it’s time to take full control of the peace process through the Player-Led Peace Conference mod.
The obvious drawback is that this is not at all ‘historically accurate’ but it does offer the player the choice to roleplay their way into a more reasonable peace table if they so desire, or just greedily skew everything in their favour. Simple, yet this mod fixes one of the most annoying things about playing with AI allies.
This mod is compatible with Version 1.10 Collie & all DLC. A Legacy version for Version 1.9 and below players can be found here.
THICC CITIES – CONTINUED (Gameplay/Map)
The amusingly accurate name delivers on its promise. Cities are now expanded into several provinces ramping up the siege drama of urban warfare. Single points and single army combat is expanded into a truly epic battlefield that does away with another layer of abstraction. A small change, but an incredibly rewarding one when such battles as Stalingrad and Moscow are finally more representative of their real history counterparts.
This mod is compatible up to Husky 1.9.2., but it doesn’t work with other non-graphics mods.
HOI4 In Real Time! (Mechanics/Balance/why)
Have you ever thought: “Gee, HOI4 goes way too fast for me! If only there was something more immersive”? Well you’re in luck! With HOI4 In Real Time!, the game takes a full 60 real-life minutes to process one in-game hour at the slowest speed. You read that correctly.
Don’t use this mod. Or do. This mod is, unfortunately, fully compatible up to 1.10 Collie.
Country Roulette (Gameplay)
World Wars can be chaotic things, especially when the player pulling the strings is constantly changing loyalties. The Country Roulette mod spins a wheel at set intervals (from 30 days to 2 years) and then plops you down in the command chair of a random new nation.
It’s a unique way to experience Hearts of Iron 4, almost akin to a new mode. You’ll end up switching sides several times, which can be great fun – after all, when you’re a master of the game, the only way to have a worthy opponent is to play against yourself. You’re usually left scrambling to sort out a great mess the AI has made for you, but at the same time, you can always put your nation in a terrible position, safe in the knowledge that you’ll be outta there long before unfriendly tanks roll into the capital.
If you’ve gotten rather entrenched in your HOI4 habits, the Country Roulette mod can be a handy way to break the mould and get a taste of more nations. At the same time, it guarantees you won’t be stuck on a tiny island with only a single division all game.
Soldier’s Radio (Cosmetic)
While the epic tones of HOI4 may be great for the high stakes drama, it’s still rewarding to sit back and listen to the music of the era and of the common soldier.
Highly immersive and strangely sombre, this music pack of over 600 songs (though not all are historically accurate) aims to create a certain atmosphere that reminds the player that he’s leading millions to death, heartache, and immortal glory.
With the addition of the new in-game radio, now is a better time than ever to try this mod out! Currently compatible with 1.10 Collie.
HOI4 – TEXTURE OVERHAUL – TERRAIN (Cosmetic)
The nitty gritty of realistic global warfare is reflected in this meticulous reworking of the terrain textures into landscapes that not only look more realistic but speak of the startling scope of the conflict. A gorgeous tour de force, no one is the poorer for this graphical upgrade which brings an added level of immersion to the rampaging divisions vying for global control. One of the best things about this mod is that it does not sacrifice performance, allowing the player to enjoy a greater expanse of visual goodies without any added lag.
Currently compatible up to 1.10 Collie.
World News Mod (Cosmetic)
One of the things HOI4 lacks is the view of how the general population fares when the world is in turmoil. World News brings back the newspaper feature of Victoria II, giving a glimpse into the life of the average person during wartime. There are some recycled items from Victoria II, but this mod goes a ways towards breaking up the monotony of the early game slog where all you can do is wait for foci to finish and factories to be built.
Fully compatible up to the current version and all DLC.
How to Mod Hearts of Iron 4
Modding has never been easier, as the Steam Workshop literally makes adding a mod as easy as clicking the subscribe button on the mod’s respective page. The mod will be automatically downloaded and will populate the mods section in HOI4’s launcher.
Here are some tips for first-timers:
- Check if the mod is up to date with the most recent patch for HoI4 (Currently 1.10 Collie). Once a new expansion comes out, you may have to wait a few days, weeks, or even months for bigger mods, until the mod is updated. Thankfully, HoI4 will give you a warning if you’re about to load a mod that isn’t up to date. Also, each mod will tell you on the side menu if it requires certain DLC.
- Still want to play that favourite mod of yours but HoI4’s latest update ruins your save game? You can always roll back your HoI4 version to continue your campaign. Check the mod pages on Steam or the Paradox forums on how to do this since it might be different for each mod and version of the game. If all else fails, ask in the comments threads for instructions!
- Check if the mods you’ve selected are compatible with the other mods you’ve downloaded. This information is usually found on each mod’s page as they usually list which mods they are able to run with.
- Remember that most mods are not compatible with Ironman as they change game balance. If you’re achievement hunting, you’ll need to find those mods that will tell you in their descriptions that they’re Ironman compatible.
- Finally, sometimes it takes a while for the HoI4 interface to properly load the mod’s latest version. Check if you have auto-updates enabled for mods and then, if you’re unsure, simply relaunch the HoI4 launcher to check if all of the mods are present and up to date.
Keep in mind that not all mods might be found on the Steam Workshop, even if the vast majority are. Simply check the Paradox forum for their listed mods and follow their instructions on their respective threads to download them.