Change how many spawn chunks stay loaded

Spawn chunks are an area around the world spawn that Minecraft keeps loaded all the time, which costs memory and processing time. Whether you can change them depends on your Minecraft version, because Mojang first made them adjustable and then removed them.

Checked against Minecraft 26.3, 1.21.9 and 1.20.5 release notes, October 2026.

What applies to your version

Look at the Version cell in the stats block of the left rail, or the JAR Manager tab, then use the matching row.

1.20.5 to 1.21.8: set the radius

1. Open the Console tab and make sure the server is Running.
2. In Send a command, type gamerule spawnChunkRadius 0 and press Enter. No leading slash.
3. The server replies that the game rule is now set to the value you gave. If the rule already had that value, it replies that the rule is already set to it instead.

The value can be anything from 0 to 32. Zero turns spawn chunks off completely, and 10 gives you the old behaviour from before 1.20.5. Mojang warns that a high value may need more memory. To see your current value, send gamerule spawnChunkRadius on its own.

1.21.9 and newer: no spawn chunks

Minecraft 1.21.9 removed fixed spawn chunks and the spawnChunkRadius game rule, so there is nothing to lower. Mojang says the game still makes sure chunks loaded by the forceload command, and chunks active because of portal activity, are fully loaded before the server starts.

If you want a redstone machine or crop farm to keep running with nobody nearby, mark the chunks yourself:

• forceload add 100 200 marks the chunk that contains block X 100, Z 200. Add a second pair of numbers to mark a rectangle. These are block coordinates, not chunk numbers, and one command can mark up to 256 chunks.
• forceload query lists the chunks marked in the current dimension.
• forceload remove all clears every marked chunk in the current dimension.

Marks belong to a dimension, so for the Nether or the End run the command in game, as an operator, while you are standing in that dimension.

What spawn chunks do to your RAM

Mojang describes spawn chunks as costing memory and performance, and cut their default size in 1.20.5 to reduce memory and CPU use. On 1.20.5 to 1.21.8 the radius game rule above is the control Mojang gives you over it. How much RAM does my Minecraft server need? explains what to expect for your player count, and Why is my server lagging? Find the cause helps you find what is actually slow.

When the change does not seem to help

• The server replies Unknown or incomplete command. See below for error. If you are on 1.21.9 or newer, the rule no longer exists. Use forceload instead.
• A farm near spawn stopped. It relied on spawn chunks. Put the radius back up, or mark its chunk with forceload.