MCUtility

Chunk Calculator

Find which chunk a block is in, where it sits inside that chunk, and which region file stores it.

Block position

Use block coordinates from the F3 screen. Decimals are rounded down to the block they’re in. Results update as you type.

Enter a block position

Type X and Z to find the chunk. Add Y to also get the chunk section.

How chunks are numbered

Minecraft divides the world into chunks of 16 × 16 blocks. The chunk number is the block coordinate divided by 16, rounded down. The position inside the chunk is what’s left over, from 0 to 15.

  • Negative coordinates round down too: block −1 is in chunk −1 at position 15, and block −17 is in chunk −2. Simply dropping the decimals would give the wrong chunk.
  • Sections split each chunk vertically into 16-block layers. They matter for lighting and some technical builds.
  • Region files in the world’s region folder each hold 32 × 32 chunks, named r.X.Z.mca.
  • The chunk bounds are in the order used by /forceload add: from X Z to X Z.

Common questions

How do I see chunk borders in game?

In Java Edition, press F3 + G. The debug screen (F3) also shows the chunk you are in.

Why is block −1 in chunk −1 and not chunk 0?

Chunk coordinates round down. Dividing −1 by 16 gives −0.0625, and rounding down gives −1.

Which file stores a chunk?

Every 32 × 32 chunks share one region file named r.X.Z.mca, where X and Z are the chunk coordinates divided by 32 and rounded down.