How to Pregenerate Your Minecraft Server World with Chunky

What pregenerating is and when it's worth it

Minecraft builds the world in pieces (chunks) as you walk. Generating a chunk costs more than loading it, so flying with elytra or several players exploring at once is what causes the most stutter. Pregenerating means asking the server to create those chunks in advance, while nobody is playing.

It's worth it if you're going to explore a lot, if you're going to use a live map (BlueMap or Dynmap) or if the server is short on RAM and CPU. If your world is small and you hardly leave base, you don't need it.

On NapNodes it's already done around spawn

When a Minecraft server is created, the system generates the terrain around the spawn point before telling you it's ready (it uses Chunky for that, and removes it if there are mods so it doesn't clash with your modpack). If you upload a modpack and recreate the world, it's generated again. Even so, the starting radius is 2,000 blocks: if you want to go further, this guide is for you.

Doing it with Chunky

1. Install Chunky

   It's a plugin (Paper, Purpur) and also a mod (Fabric, Forge, NeoForge). In the panel, “Mods & plugins” finds it on Modrinth for your version and loader. Restart the server.

2. Choose the world and centre

   In the panel console: “chunky world world” (the main world, which is the one explored most) and “chunky center 0 0”, or “chunky spawn” to centre it on the spawn point.

3. Set the radius

   “chunky radius 3000” generates a square of about 6,000 × 6,000 blocks around the centre. With 3,000–4,000 that's already a huge amount of terrain.

4. Start

   “chunky start”. With “chunky progress” you see how much is done and how much is left, and with “chunky pause” or “chunky cancel” you stop it; when you resume it with “chunky continue” it carries on where it left off.

5. Best with nobody online

   Generating uses a lot of CPU. Do it overnight or with the server empty: while it runs, players will notice stutter (if they notice it afterwards, the lag guide picks up from there).

How long it takes and how much space it uses

It depends on the CPU: from a few hundred chunks per second to a lot fewer on a modest machine, and the time grows with the square of the radius (double the radius, four times the work). Disk grows the same way: a radius of 5,000 blocks can take up several GB, so check your plan's space before launching it (on NapNodes, each server's disk is changed in “My servers” → “Adjust”, using whatever you have free).

A big pregeneration also makes backups bigger, because the world weighs more. If you're never going to set foot in those areas, it's wasted space.

Put a border on the world

Pregenerating doesn't help much if someone later walks beyond the radius. With “/worldborder set 6000” the world ends right where the pregenerated area ends (the diameter is twice the radius). Chunky also has “chunky worldborder” to copy the border you already have.

Frequently asked questions