Forge Mod Loader

Minecraft Forge is the loader most classic modpacks were built on, from the 1.7.10 and 1.12.2 tech packs to the large 1.20.1 collections people still play today. It adds nothing you can see in a world. What it does is patch the game at startup, read every jar in the mods folder and give those mods a shared set of hooks, so a recipe viewer, a building wand and a new ore can run side by side without overwriting each other’s code. Our list covers Forge from 1.5.2 to 1.21.5. The Forge team itself has kept going and now builds for the year-numbered releases as well, 26.3 included.

Installing Forge from the installer jar

Forge is not a mod you drop into a folder. It ships as a small Java program that adds a new installation to the official launcher. Before running it, start the plain version you want (1.20.1, say) once from the launcher and close the game. The installer writes into the launcher’s files, and if it cannot find them it stops with “There is no Minecraft launcher profile… you need to run the launcher first!”

1. Pick the installer for your exact game version below. A 1.20.1 build will not install onto 1.20.4.
2. Double-click the jar. If Windows opens it like a zip archive, right-click it and choose Open with → Java. No Java in that menu means you need a Java runtime installed system-wide; the copy bundled with the launcher is invisible to Windows.
3. Leave Install client selected and check that the path points to your .minecraft folder (on Windows it lives in %appdata%). Install server builds a dedicated server folder, and Extract only unpacks the jar.
4. Press OK. The installer downloads libraries and patches the game, which can take a minute.
5. Open the launcher, choose the new forge installation from the list next to Play and start it.

The first launch is slower than vanilla. Once the title screen appears, the bottom-left corner shows the Forge build and how many mods are loaded, and a Mods button lists them. After that first start the mods folder exists inside .minecraft, ready for your jars.

Java versions and Forge builds

Which Java goes with which Minecraft

Forge runs on the same Java as the game, and Mojang raised that requirement several times:

• 1.12.2 and older: Java 8. Forge for these versions crashes on anything newer.
• 1.17 and 1.17.1: Java 16.
• 1.18 to 1.20.4: Java 17.
• 1.20.5 to 1.21.11: Java 21.
• 26.1 onward: Java 25.

Versions 1.13 to 1.16.5 also expect Java 8. The official launcher downloads the right runtime by itself, and the forge installation borrows it from the vanilla version underneath. Problems appear when you set a custom Java executable in the installation settings, use another launcher, or start a server by hand. Two crash messages give it away. “ClassCastException … URLClassLoader” means an old Forge (1.12.2 or earlier) is running on Java 9 or newer. “UnsupportedClassVersionError” means the Java is too old for that build.

Recommended or latest?

For each Minecraft version the Forge file server marks a Recommended build, one the team considers stable, and a Latest build with the newest fixes. For 1.20.1 the recommended build is currently 47.4.10 and the latest is 47.4.26. On 1.8.9 both labels point to 11.15.1.2318, because work on that branch finished long ago. Most installers in our list are early builds (47.0.1 for 1.20.1, for example). They handle small packs, but newer mods often declare a minimum Forge version and the error screen will name it. If that happens, take a newer installer from the Forge project’s own file server. Reinstalling Forge never touches your mods folder.

Forge, NeoForge or Fabric?

In July 2023 almost the entire Forge team, including original author cpw, forked the project as NeoForge. LexManos, whose company Forge LLC owns the Forge name and assets, was the notable person who did not join. On 1.20.1 the fork stayed close enough that most Forge mods still loaded on it. From 1.20.2 NeoForge renamed its code packages and switched to its own numbering (20.2.x), and mods stopped being interchangeable between the two.

• An older pack, or a mod that only exists for 1.7.10, 1.12.2, 1.16.5 or 1.20.1: Forge.
• Content mods on 1.21 and later: read the mod page first. Many large projects moved to NeoForge, and some no longer release a Forge build at all.
• Performance mods, shaders, quick updates to new releases: Fabric. Sodium and Lithium started there and added NeoForge builds from 1.21, not Forge ones.
• Quilt: a Fabric offshoot that loads most Fabric mods. Use it only when a mod asks for it.

When Forge refuses to start

• A Fabric mod in the folder. Jars made for Fabric are not Forge mods, even when the name matches. Forge won’t run them, and mods that need them fail too. Get the Forge build or remove the file.
• A mod for another game version. A 1.20.1 mod will not load on 1.21.1 and vice versa. The crash report names the file.
• A missing library. The error screen lists what is absent. Multi-loader mods often want Architectury API or Cloth Config API; take the Forge build for the same version.
• Two copies of one mod. An old and a new jar side by side cause a duplicate-mod error. Delete the older one.
• Large pack, frozen loading bar. Give the installation more memory: Installations → Edit → More options, then raise the -Xmx value in the JVM arguments.

Questions players ask about Forge

Can I use Sodium on Forge?

Not the original. Sodium runs on Fabric and, from 1.21, on NeoForge. On Forge 1.16.5 to 1.20.1 players use Embeddium, a community port of Sodium. Lithium has the same split. Our FPS mods list shows which builds exist for each loader.

How do I add OptiFine to Forge?

Put the OptiFine jar in the mods folder like any other mod instead of running its own installer. Every release on the official OptiFine download page names the Forge build it was made against: HD U I6 for 1.20.1 lists Forge 47.2.18, newer than our 47.0.1 file. If OptiFine crashes on startup, update Forge before blaming the mod.

Which Forge do I need for 1.8.9?

Any 1.8.9 build runs the old PvP-era mods, but if one asks for a newer Forge, 11.15.1.2318 is the final build and carries both labels. The launcher gives it Java 8 automatically. After that, a recipe viewer like Just Enough Items is the usual first addition.

Download Forge for Minecraft