Exploring new biomes is awesome. Exploring with huge freezes every time a new chunk loads? Not so much. On a Minecraft server, terrain generation is one of the most CPU-hungry tasks, and it’s a classic cause of lag spikes when your players go adventuring.

Chunk-Pregenerator fixes that by pre-generating your world before players reach it. The result is smoother exploration, fewer stutters, and a server that can breathe in 2026 even with an active community.

In this guide, you’ll learn what Chunk-Pregenerator does, how to start a pregen depending on your mod version, and how to run it with or without WorldBorder.

Chunk-Pregenerator: what it does

Chunk-Pregenerator is a mod that generates a selected area of your world in advance (by chunks or by blocks). The goal is simple: avoid forcing the server to calculate brand-new terrain “on the fly” when a player enters unexplored land.

In practice, pregen helps you:

• Reduce exploration lag

• Keep TPS more stable while traveling

• Prepare a world before launch day

• Limit CPU spikes during gameplay

You’ll find the official mod page (commands, versions, documentation) here: https://www.curseforge.com/minecraft/mc-mods/chunkpregenerator

📝 Note: The mod is listed as compatible from Minecraft 1.7 to 1.21, depending on the builds available on CurseForge.

Install Chunk-Pregenerator on your server

Before you can pre-generate anything, the mod must be installed server-side (Forge or Fabric depending on your setup). If you want a step-by-step install guide, follow: https://minestrator.com/blog/article/installer-mods-serveur-minecraft

⚠️ Warning: Always run a pregen on a stable server with a fresh backup. Massive generation can fill your disk faster than you expect.

Start a pregen on 1.13+

From mod version 1.13 and above, the command syntax changes. For the full list, check the official page: https://www.curseforge.com/minecraft/mc-mods/chunkpregenerator

To start a radius-based generation, you’ll typically use a command like this:

/pregen start gen radius GenExample SQUARE 0 0 100

It follows this format:

/pregen start gen radius GenerationName Shape X Z Size

• GenerationName: any name you want (example: SpawnPreGen)

• Shape: SQUARE or CIRCLE

• X and Z: the center of the area

• Size: in chunks, or in blocks with a b

If you add a b after the number, the distance is interpreted in blocks instead of chunks, which is handy for precise borders.

💡 Tip: Use clear task names (example: overworld_spawn_3k) so you don’t get lost when running multiple pregens.

Pre-generate with WorldBorder (1.13+)

If you want a clean, easy method, you can rely on WorldBorder. It defines a square map limit and can also stop players from reaching freshly generated chunks too early.

WorldBorder commands are documented here: https://minecraft.fandom.com/wiki/Commands/worldborder

Start by setting the center (only X and Z matter):

/worldborder center X Z

Then set the size. This value is a diameter in blocks, not a radius:

/worldborder set DIAMETER

Once the WorldBorder is ready, generate everything inside it:

/pregen start gen worldborder

💬 Good to know: WorldBorder is perfect for “season” servers with a deliberately limited map.

Useful commands on 1.13+

To control your generation job day-to-day, these are the commands you’ll use the most:

• /pregen pause: pause the job

• /pregen resume: resume the job

• /pregen stop: stop the job

• /pregen info listen: track progress

• /pregen info unlisten: stop tracking

Start a pregen on 1.4.3 to 1.12.2

On older versions of the mod (1.4.3 to 1.12.2), the command format is different. The dedicated documentation is here: https://www.curseforge.com/minecraft/mc-mods/chunkpregenerator/pages/112-documentation/command-suggestions

The basic command looks like this:

/pregen gen startradius square 0 0 100

This generates an area of 100 chunks in the dimension where the player running the command is located. If you run it from the console, it defaults to the Overworld.

You can also request a block distance by prefixing the value with b:

/pregen gen startradius square 0 0 b1000

Use WorldBorder on 1.4.3 to 1.12.2

Just like on 1.13+, you can define an area with WorldBorder, then tell the mod to generate everything inside it. WorldBorder commands are here: https://minecraft.fandom.com/wiki/Commands/worldborder

Set the center, then the diameter:

/worldborder center X Z
/worldborder set DIAMETER

Then start the WorldBorder-based generation:

/pregen gen startWorldBorder

Useful commands on 1.4.3 to 1.12.2

On these versions, the control commands don’t use exactly the same names:

• /pregen stop: stop generating

• /pregen continue: resume generating

• /pregen clear: stop and remove the task

• /pregen info listen: track progress

• /pregen info unlisten: stop tracking

Pick the right pregen size

For a “classic” survival server, a radius of around 3000 blocks is often enough (about 185 chunks). Keep in mind that going from 3000 to 4000 blocks isn’t “just 1000 more”: surface area jumps from roughly 9 million to 16 million blocks, which is close to double.

The best timing is when the server is empty, like early morning or late night. Pregen can hit your CPU hard, and you don’t want extra lag right when your players are trying to chill and mine.

⚠️ Warning: A bigger pregen also increases world size on disk. Monitor your storage before aiming for “infinite map” vibes.

Questions frequent

Should I pregen with players online?

It’s possible, but it’s rarely a good idea. Pre-generating chunks can spike CPU usage and cause TPS drops, especially during exploration-heavy hours. For best results, run pregen when the server is empty and keep an eye on the console.

Does pregen reduce lag forever?

It reduces lag linked to new chunk generation. You can still get lag from mobs, redstone farms, heavy mods, or plugins. Think of pregen as removing one major source of spikes, not a magic “no lag” button.

How do I choose between radius and WorldBorder?

Use radius if you want a flexible shape (square or circle) centered on a spot like spawn. Use WorldBorder if you want a strict square limit for a season server, and you want players to stay inside the generated area.

Conclusion

Chunk-Pregenerator is one of the best ways to reduce exploration lag on a Minecraft server: generate the area once, and your players get smooth chunk loading from day one.

Need help tuning your server setup? Browse our FAQ or reach out via MineStrator support to save time and avoid painful mistakes.