Slime Chunk Finder

Slime chunks are the 16×16 columns where slimes can spawn underground, below Y 40. This page paints them as a green overlay for your seed and version. Turn on Grid lines to see chunk borders, type your base's X and Z and press Go! to center the map there, then pick a highlighted chunk for the farm.

How a chunk becomes a slime chunk

Roughly one chunk in ten qualifies, but the two editions decide it differently. Java mixes the world seed with the chunk's X and Z, seeds a random generator with the result and checks whether its next number out of ten is zero, so every seed has its own pattern. Bedrock leaves the world seed out entirely and uses only the chunk coordinates, so every Bedrock world shares one pattern.

That is why the Bedrock overlay looks identical whatever seed you paste, and why a Java slime map made for one seed is useless for another.

From a green square to a working farm

Chunk borders sit on multiples of 16: the chunk holding X 1000 runs from X 992 to 1007. In Java, F3 + G outlines chunk borders in-game, so mark the corners before you dig.

• Hollow out the chunk below Y 40 and stack several spawning floors with at least three blocks of headroom, enough for the largest slimes.
• In Java, light does not stop slime-chunk spawning, so light the floors freely to keep other mobs out.
• Java mobs spawn between 24 and 128 blocks from the player: wait close enough, but not on top of the floors.

Slimes that ignore the overlay

Swamps and mangrove swamps spawn slimes at the surface too, between Y 51 and 69 in Java, more often under a full moon. That is a separate rule from the underground one mapped here. Every Overworld finder on this site has the same Slime chunks checkbox, so you can check for one next to a village or a swamp hut.

Frequently asked questions

Why is the Bedrock slime map the same for every seed?

Bedrock works out slime chunks from the chunk coordinates alone; the world seed never enters the calculation. A slime chunk in one Bedrock world is a slime chunk in all of them.

My farm sits in a highlighted chunk but nothing spawns. What is wrong?

Check that the floors are below Y 40, the difficulty is not Peaceful, and the edition and version match your world. A Java overlay drawn from the wrong seed shows a completely different pattern, so confirm the seed with /seed.