MCASelector is a popular tool that can be used to reduce the size of a Minecraft server's world files. In this guide, we will show how to use it to reduce your world size.

How does it work?

MCASelector works primarily by scanning through all of your server's chunks and deleting anything that doesn't match a criteria. This is particularly useful because some servers have very large worlds due to chunk exploration, but players don't care about the chunks themselves. These chunks can be deleted by MCASelector to free up large amounts of space.

We typically want to delete chunks that haven't been occupied for very long. For this purpose we will use the InhabitedTime selector, but MCASelector has many other modes that can also be used. It can also be used for more than just deleting chunks.

How to delete unused chunks?

  1. Download the MCASelector jar file.
  2. Place the jar file in your server directory, in the same location as your main server.jar file
  3. Ensure that your server is stopped and not running
  4. Run the following command to delete chunks that haven't been occupied for at least 5 minutes: java -jar mcaselector.jar --mode delete --world "world" --query "InhabitedTime < 5 minutes".
  5. Repeat the command for all worlds that you want to delete. The time can also be modified to your choosing


  • We recommend taking a backup before deleting chunks in case anything goes wrong. You wouldn't want to accidentally delete your entire world!
  • In order to avoid needing to trim your world if you begin to run out of space, we recommend pre-generating your world and setting a border.
  • If you are using Pufferfish Host, you can use MCASelector by uploading the jar file, selecting it in the startup tab, and using the extra flags option to build the rest of the command.