How to Install Forge (Java Mod Loader)

Guide Java Bedrock

Quick answer: Download the Forge installer free from files.minecraftforge.net, run it and install the client - a Forge profile appears in the launcher. Drop your mods into .minecraft/mods and play. Forge and NeoForge mods must match your exact Minecraft version.

What you need

Minecraft Java Edition
The free Forge installer from files.minecraftforge.net
Forge mods matching your Minecraft version

Step by step

Launch your target Minecraft version once in the official launcher - Forge can only install over versions that exist on your PC.
Download the installer from files.minecraftforge.net - free, and the only official source. Pick the version matching your game.
Run the downloaded .jar and choose Install client. It creates a Forge profile in the launcher.
Download your Forge mods from CurseForge or Modrinth - check each mod lists Forge (or NeoForge) and your exact game version.
Put the mod .jar files into .minecraft/mods. Launch once to generate the folder if it is missing.
Select the Forge profile and play. The Mods button on the title screen shows what loaded.
Crashes at startup almost always mean a version mismatch: mod for 1.20.1 does not run on 1.21. Remove the newest mod and re-check.
Newer mods may target NeoForge instead - the installer works the same way, from neoforged.net.

Java vs Bedrock

Java Edition only. Bedrock does not support Forge or mods - it uses add-ons.

Versions: Forge publishes builds for every Minecraft release, though big content mods sometimes lag a version behind. NeoForge is the modern fork many mods moved to after 1.20.2.

Frequently asked questions

Is Forge free?

Yes - Forge is free from files.minecraftforge.net. Sites charging for installers or modpacks are scams.

Forge or Fabric?

Forge/NeoForge host the big content mods (Create, Twilight Forest); Fabric is lighter and faster to update. Many players install both profiles and pick per modpack.