How to Pre-Generate a World on a Minecraft Forge or NeoForge Server

Generating new chunks is one of the heaviest things a server does. Pre-generating the world ahead of time means players exploring don't cause lag.

Install Chunky

1. Open Package Manager, click Browse packages, search for Chunky, and install the Forge or NeoForge build.
2. Package changes are queued and applied the next time the server starts, so restart it from Console when you're done.

Set a border first

Set a world border so the world has a fixed size:

worldborder set 10000

See How to Add a World Border.

Generate

Run these in Console:

chunky worldborder
chunky start

chunky worldborder matches Chunky's area to the border. Check progress with chunky progress. You can chunky pause and chunky continue it.

Tips

• Run it when few players are online; it uses a lot of CPU.
• A 10,000-block world (5,000 each way) takes a while and needs disk space. Start smaller if your plan is tight on disk.
• Modpacks with heavy world generation are slower to pre-generate.

The same steps work on Fabric and Paper; see How to Pre-Generate a World.