Chunky Commands: How to Pre-Generate a Minecraft World illustrated for the CraftLands Minecraft docs

MINECRAFT · PERFORMANCE

Docs Writer

Published July 26, 2026

UPDATED 13 DAYS AGO

Chunky Commands: How to Pre-Generate a Minecraft World

The Chunky commands to pre-generate a Minecraft world: set the radius, start, pause, continue, cancel and check progress from the console.

QUICK ANSWER

Run chunky radius 5000 and then chunky start in the server console. chunky progress shows how far it is, chunky pause stops it and saves the task for chunky continue, and chunky cancel stops it for good. There is no chunky stop command.

Fact

Chunky has no stop command: chunky pause saves the task for chunky continue, chunky cancel deletes it, and chunks already generated stay either way.

Fact

The radius is in blocks from the center, so chunky radius 5000 covers a 10,000 by 10,000 block square, 393,129 chunks.

What is Pre-Generation

World pre-generation means generating chunks in the background of your server before players explore them. The goal is to cut the lag that comes from the server building new terrain while players walk into it.

Chunky is a free, open-source plugin and mod that does this, with over 18 million downloads on Modrinth.

What is Chunky

Chunky is a plugin for Paper, Spigot and Folia and a mod for Fabric, Forge and NeoForge. It runs on the server only, so players do not need to install it. It generates chunks in the background and saves them, so the server later loads that terrain from disk instead of making the CPU build it on the fly.

Pre-generating huge areas takes gigabytes of storage. Start with a 5,000-block radius and increase it later if you need more.

How to Install Chunky

To install Chunky, you will have to follow these steps:

1Open and log in to your server's dashboard.
2Open the Mods section in the Sidebar (Plugins on a Paper or Spigot server).
3Search "Chunky" on the Searchbar.

4Click the Install icon next to Chunky.
5Select the version that matches your server and click Install again.

Restart the server so Chunky loads. On Fabric, install Fabric API the same way, since Chunky needs it.

Verify Installation

Open the Console and type chunky. If Chunky loaded, it prints its help menu. If nothing comes up, check that the Chunky .jar is in the 'mods' folder (or 'plugins' on Paper) in Files, then restart the server.

How to Pre-Generate With Chunky

Installing Chunky does not start anything. Run these commands in the Console tab without a leading slash. In game, put / in front of each one.

Choose the world. The Nether is usually world_nether and the End world_the_end (the_nether and the_end on some setups):

chunky world world

Set the center. chunky spawn uses the world spawn, chunky center 0 0 uses coordinates, and in game chunky center alone uses where you stand:

chunky spawn

Set the radius in blocks. The Chunky wiki suggests starting at 5000:

chunky radius 5000

Start the pre-generation:

chunky start

Radius in Blocks and Chunks

The radius counts blocks from the center, and the default shape is a square, so chunky radius 5000 covers 10,000 by 10,000 blocks. Add c to give chunks instead (chunky radius 625c is 10,000 blocks) or k for thousands (chunky radius 10k).

Radius	Area (square)	Chunks
500 (Chunky's default)	1,000 x 1,000 blocks	4,225
1,000	2,000 x 2,000 blocks	16,129
5,000	10,000 x 10,000 blocks	393,129
10,000	20,000 x 20,000 blocks	1,565,001

Doubling the radius means about four times the chunks to generate and store. A circle (chunky shape circle) covers about 79% of the square. For a disk estimate, the Chunky wiki points to tgb's World Size Calculator.

Chunky Commands

The commands you will use most, from the Chunky wiki, which has the full list. The current release on 30 September 2026 is 1.5.3 for Paper and Fabric and 1.5.4 for Forge and NeoForge.

Command	What it does
`chunky start`	Starts generating the current selection.
`chunky pause`	Stops the task and saves its progress.
`chunky continue`	Resumes a paused or saved task.
`chunky cancel`	Stops the task and deletes it. It cannot be resumed.
`chunky progress`	Shows progress in game. The console shows it on its own.
`chunky world <name>`	Picks the world or dimension.
`chunky spawn`	Centers the selection on the world spawn.
`chunky center <x> <z>`	Centers the selection on coordinates.
`chunky radius <blocks>`	Sets the radius, in blocks unless you add c.
`chunky shape <shape>`	Square by default. Circle and others are available.
`chunky worldborder`	Copies the world border's center and radius.
`chunky selection`	Shows what the next start will generate.
`chunky trim`	Deletes chunks outside the selection. It cannot be undone.

How to Stop Chunky

There is no chunky stop command. Use chunky pause when you want to finish later: the task is saved and chunky continue picks it up where it stopped. Use chunky cancel to drop the task for good.

Either way, the chunks already generated stay in the world. Only chunky trim deletes chunks, and that cannot be undone, so take a backup first and restart the server after it.

How to Check Chunky Progress

While a task runs, the console prints the chunks done, the percentage, an ETA and the rate in chunks per second. In game, /chunky progress shows the same line. If the updates flood the console, chunky quiet 30 prints one every 30 seconds and chunky silent turns them off. On Fabric, Forge and NeoForge, Chunky also shows a progress bar at the top of the screen to operators while a task runs, and chunky silent hides it. The Paper plugin has no bar, so use chunky progress there.

Pause Chunky While Players Are Online

Chunky has no setting that pauses it when players join, so run chunky pause before your players come on and chunky continue once the server is empty. On CraftLands you can put this on a timer: the panel's Schedules page runs console commands at times you set, so one schedule can send chunky continue at night and another chunky pause before the evening.

Two settings decide whether it keeps going. Since Minecraft 1.21.2, a server pauses itself 60 seconds after the last player leaves (pause-when-empty-seconds in server.properties), and Chunky's FAQ asks for -1 while you pre-generate. A task also does not resume after a restart unless continue-on-restart is true in plugins/Chunky/config.yml ("continueOnRestart": true in config/chunky/config.json on Fabric, Forge and NeoForge); otherwise it waits for chunky continue.

Important Notes

Keep the following in mind:

Chunky needs server software that loads plugins or mods: Paper, Spigot or Folia for the plugin, Fabric, Forge or NeoForge for the mod. You can change your server software from the panel.
You must restart your server after installing Chunky to activate it.
Chunky runs only on the server, so players do not download it.
Generation speed depends on the server's CPU and disk. Chunky's FAQ recommends a CPU with high single-thread speed, a fast SSD and at least 4 GB of RAM (the RAM calculator sizes memory for your mods and players). Every CraftLands Minecraft server runs on a Ryzen 9 9950X with NVMe storage.

Where to Go Next

Match the area with a world border so players stay inside the generated chunks. Chunky's radius is half the border's width: a 5000 radius centered on 0 0 matches worldborder set 10000, and chunky worldborder copies an existing border. If the server still lags after pre-generating, run a spark profile and paste the link into the free Spark report analyzer to see which plugin or mod is using the tick.

Is there a way to make Chunky faster?

Chunky already runs as fast as the server lets it, so the gains come from the server. Chunky's FAQ suggests Aikar's flags in the start script, Paper for its faster chunk handling, pausing map renderers such as Dynmap until the task finishes, and Lithium on Fabric. The CPU, SSD and RAM notes above matter as well.

Why is Chunky not working?

Type chunky in the console first. No help menu means it did not load: check that the jar matches your server software and Minecraft version, that Fabric API is installed on Fabric, and restart. If the help menu shows but a command fails in game, your account needs the matching permission, such as chunky.command.start. If generation stalls on a modded server, test with only Chunky installed, since Chunky's FAQ lists mods such as C2ME and Starlight that can crash or stall world generation.

Does Chunky work with Distant Horizons?

Yes. Distant Horizons builds its LODs while Chunky generates chunks, though pre-generated chunks and LODs are not the same thing. If holes show up, Chunky's FAQ passes on the Distant Horizons developers' advice: run Chunky first with Distant Horizons removed or its Distant Generation turned off, or fill the gaps afterwards with their LOD pre-generator.

Can Chunky regenerate chunks?

No. Chunky skips chunks that already exist and only generates the missing ones. To rebuild an area, restore a backup from before those chunks were made, or take a backup and delete them with trim's inside option, for example chunky trim world square 0 0 1000 1000 inside (plain chunky trim deletes everything outside the selection instead). Restart the server, then run chunky start again.