Coordinate / Chunk / Region Calculator
Enter X, Y, Z and the calculator instantly shows the chunk, the region, the save file and the block position inside each of them.
How we calculate
The world is split into 16×16-block chunks horizontally, and chunks into 32×32-chunk regions (that is, 512×512 blocks). A chunk or region number comes from dividing the coordinate and rounding toward negative infinity, not simply truncating the fractional part — so negative coordinates convert just as reliably as positive ones.
Vertically a chunk is split into 16-block sections. In current versions section numbering starts at the very bottom of the world, so a section index can be negative. The game names a region's save file after the region's coordinates: r.X.Z.mca.
The calculator also shows the chunk's and the region's bounds in world coordinates — useful for seeing exactly where the current chunk ends and the next one begins.
Sources
checked 1 September 2026
Questions and answers
How do I work out a chunk number by hand?
Divide the X or Z coordinate by 16 and round toward negative infinity, not toward zero. Simply truncating the fractional part gives the wrong chunk for negative coordinates — the calculator converts correctly in both directions.
Why is a section index sometimes negative?
In current game versions the Overworld reaches down to -64, and sections are numbered from the very bottom of the world — so the bottom 4 sections carry a negative index.
What is an .mca file and why do I need its name?
It is the save file for one 32×32-chunk region. A name like r.X.Z.mca is useful when you need to find a specific region on disk — for a manual backup, say, or to delete a corrupted part of the world.
Does the height warning also apply to the Nether?
Not directly — the Nether and the End are only 256 blocks tall, so their legal Y range differs. The warning is aimed at the Overworld and should be read as a hint, not a hard error.
Unofficial tool. Not affiliated with the developers or publishers of Minecraft.