Chunk calculator
Find which chunk and region file any block is in, its position inside the chunk, and the chunk's corners.
- Chunk
- Position in chunk
- Chunk corners
- Region file (Java)
How to use it
Enter a block's X and Z coordinates. The calculator shows which chunk the block is in, where it sits inside that chunk, the coordinates of the chunk's corners, and which region file stores it.
What a chunk is
The world is divided into chunks: columns 16 blocks wide, 16 blocks long, and the full height of the world. The game loads, saves and updates the world one chunk at a time.
| Value | How it's calculated |
|---|---|
| Chunk X, Z | block X ÷ 16 and block Z ÷ 16, rounded down |
| Position inside the chunk | the remainder, from 0 to 15 |
| First block of the chunk | chunk X × 16, chunk Z × 16 |
| Region file (Java) | chunk X ÷ 32 and chunk Z ÷ 32, rounded down, saved as r.X.Z.mca. Bedrock stores worlds differently. |
Rounding down matters for negative numbers: block X −1 is in chunk −1, not chunk 0.
Why chunks matter
- Farms and redstone: chunks only update while they're loaded. Keep a machine inside one chunk where you can, so half of it never stops while the other half runs.
- Slime chunks: slimes spawn below Y 40 only in certain chunks. Knowing chunk borders helps you build a slime farm that fills the whole chunk.
- Spawn chunks: in Java Edition, chunks around the world spawn point stay loaded even when no one is near, which makes them popular for farms.
- World editing: tools that copy, trim or reset parts of a world usually work in whole chunks or region files.
Seeing chunk borders in game
In Java Edition, press F3 + G to show chunk borders, and the F3 screen shows the chunk you're standing in. In Bedrock Edition, the coordinates display shows your position, and this calculator gives the chunk.