Chunker: a free Java and Bedrock world converter

What Chunker is

Chunker is maintained by Hive Games, the company behind The Hive server. The code lives on GitHub in the HiveGamesOSS/Chunker repository under the MIT license. In the README the authors say the project receives funding from Mojang Studios. Even so, Microsoft's documentation for creators (Microsoft Learn) notes that Chunker is the work of external authors, not a product of Mojang or Microsoft.

The program comes in two forms: an app with a graphical interface (Electron) and a CLI version for the terminal. You can download both from the Releases section. Version 1.21.0 has installers for Windows (x86 and ARM64), macOS (Intel and Apple Silicon) and Linux (AppImage, deb, zip).

Supported game versions

The list of formats from the project README (as of version 1.21.0):

In its settings, Chunker labels the new year-numbered Bedrock versions as 1.26.x, for example 1.26.60. Release 1.21.0 added initial support for Bedrock 26.60, the version scheduled for October 27, 2026. It also reduced memory use for large Bedrock worlds and fixed old blocks that turned into air in the Bedrock world. The previous release, 1.20.0 from September 2, 2026, introduced initial support for Bedrock 26.50 and fixes for Java 26.3.

How to convert a world

Before you start, copy the world to a safe place. Chunker saves the result to a separate folder, but a backup will spare you a lot of stress if something goes wrong.

1. Download and run the Chunker app for your system.
2. On the loading screen, choose Choose world folder and point to the main world folder, the one that contains the level.dat file. You can also click Select archive and choose a .zip or .mcworld file. In Bedrock you can create a .mcworld file with the Export World button in the world settings.
3. Pick the target edition and game version from the list.
4. Click Convert. Advanced Mode only comes in handy for unusual worlds, for example ones with custom blocks or dimensions.
5. When it finishes, click Save and save the result. You get a Bedrock world as a .mcworld file that you open in the game. Copy a Java world to the saves folder.

According to Microsoft Learn, most worlds convert in a few minutes. We cover where to find the world folders on each platform in our guide on how to install a map in Minecraft.

What Chunker will not transfer

Microsoft Learn lists what Chunker transfers without trouble: world settings, blocks, biomes, block entities (for example chest contents), several dimensions at once, items in containers and maps. When you change editions, however, you will lose:

• Entities, that is mobs, animals and items lying on the ground. Paintings and item frames are the exception.
• Player inventories, so put the contents of your inventory in a chest before converting.
• Structure data, that is information about where villages or strongholds stand. The blocks of the buildings stay, but the game may not recognize them as structures.

If you save the world in the same version it came from, Chunker keeps entities and inventories. Do not expect redstone contraptions to carry over fully either: Java and Bedrock differ in how pistons and circuits work, which we explain in the Java vs Bedrock comparison.

Chunker on the command line

The CLI version is useful for servers and automation. The .jar file requires Java 17 or newer, and Releases also has ready-made executables that need no separate Java. An example from the documentation that converts the world my_world to the Bedrock 1.20.80 format:

java -jar chunker-cli-VERSION.jar -i "my_world" -f BEDROCK_1_20_80 -o output

The -i parameter points to the input folder, -o to the output folder, and -f to the target format in the form EDITION_X_Y_Z, for example JAVA_1_20_5. The value INPUT keeps the source version. By default the app uses up to 75% of the available RAM. For very large worlds you can set the limit manually, for example Chunker.exe -Xmx8G for 8 GB.

Frequently asked questions

Is Chunker free?

Yes. Chunker is free and open source under the MIT license. Ready-made versions for Windows, macOS and Linux are in the Releases section of the project's GitHub page. Amulet, another popular world editor and converter, is paid.

Is Chunker a Mojang program?

No. Chunker is maintained by Hive Games, the company behind The Hive server. According to the README, the project is funded by Mojang Studios, but Microsoft's documentation describes it as a tool from external creators, not a Mojang or Microsoft product, and you use it at your own risk.

Does Chunker transfer mobs and player inventory?

Not when you change editions. Chunker does not convert entities (apart from paintings and item frames) or player inventories. It keeps them only when you save the world in the same format it came from. After the conversion you will have to bring animals back and breed them again, and put your inventory items in chests beforehand, because Chunker does transfer the contents of containers.

Related pages

• How to move a world from Java to Bedrock - step by step with Chunker and Amulet
• Amulet - world editor and converter
• Blockbench - 3D model editor for Minecraft
• Chunkbase - structure and biome map from a seed
• All Minecraft tools