Slime chunks
Where slimes spawn underground: a chunk map around you from the world seed, the nearest slime chunks, and their borders in blocks. The formula comes from the game's code, and for Java it is checked against Java itself.
World
Chunk map
slime chunks on the map: 35 of 425
Blocks X 0 to 15, Z 0 to 15. Here slimes only spawn in swamps and mangrove swamps.
How slime chunks work
The world is split into chunks — columns 16 by 16 blocks from bedrock to the sky. A chunk number is the block coordinate divided by 16 and rounded down: block X = −1 is already in chunk −1. Every tenth chunk is a slime chunk, and which ones depends on the world seed in Java and only on the coordinates in Bedrock.
For a farm, dig out the whole chunk below height 40 and build platforms three blocks apart — slimes need room to spawn. The more empty floors in the chunk and the fewer caves around it, the faster the farm runs.
Frequently asked questions
How do you find a slime chunk?
In Java, get the world seed with /seed and enter it with your coordinates — the calculator shows the map and the nearest slime chunks. Chunk borders show in game with F3+G. In Bedrock no seed is needed: slime chunks are the same in every world.
At what height do slimes spawn?
In a slime chunk, below height 40 at any light level, which is why farms are built deep underground. Outside slime chunks slimes only spawn at the surface in swamps and mangrove swamps, at night and more often under a full moon.
How many chunks are slime chunks?
One in ten. The game mixes the world seed with the chunk coordinates and rolls a number from 0 to 9: the chunk is a slime chunk if it rolls zero. So wherever you are, a slime chunk is usually a few chunks away.