Minecraft Slime Chunk Finder

What slime chunks are

Minecraft divides the world into chunks: columns of 16 × 16 blocks that run from the bottom of the world to the top. About one chunk in ten is a slime chunk. Underground, below Y 40, slimes can spawn in these chunks no matter how bright it is, which makes them the best place for a slime farm and a steady supply of slimeballs for sticky pistons, leads and slime blocks.

Nothing in the world marks a slime chunk. The game decides it with a fixed formula:

• Java Edition feeds the world seed and the chunk coordinates into Java's random number generator. If the first number from 0 to 9 it produces is 0, the chunk is a slime chunk. Different seeds give different slime chunks.
• Bedrock Edition ignores the seed. Slime chunks sit at the same coordinates in every Bedrock world, so a Bedrock slime chunk you look up here is valid in any world. The Bedrock formula is not published by Mojang; this tool uses the version reverse-engineered by the community, which matches known Bedrock slime chunks.

To get a chunk's coordinates, divide the block coordinates by 16 and round down. Block X −100 is in chunk −7, because −100 ÷ 16 = −6.25, which rounds down to −7. The finder does this for you and shows the block range of every chunk.

How to use the slime chunk finder

1. Pick your edition. Java needs your seed, Bedrock does not.
2. Paste your seed (Java). Use the number that /seed prints. Negative seeds and text seeds both work.
3. Enter your X and Z coordinates from the F3 screen (Java) or the coordinates display (Bedrock) and press Go to. The white dot on the map is you.
4. Read the map. Green squares are slime chunks. Hover or tap a square for its chunk number and block range, drag to look around, and use the + and − buttons to zoom.
5. Use the list. The table shows the ten slime chunks closest to you, with their block ranges, the distance to the center of each chunk and the direction to walk. Show highlights a chunk on the map.

Press Copy share link to share the map with friends on the same world. The link contains the seed and position, so only share it with people who may know your seed.

Slime spawning rules

In slime chunks

• Slimes spawn in slime chunks below Y 40, at any light level and in any weather. Torches do not stop them, so you can light the farm to keep other mobs out.
• Each spawn spot needs room for a large slime: about 2.1 × 2.1 × 2.1 blocks free of solid blocks and liquids. Any block inside that space, even a glass pane, can block a spawn. Small and medium slimes cannot spawn in a 2-block-tall gap either, so farms usually leave a 2½-block gap, using slabs.
• In Java Edition slimes spawn in groups; in Bedrock they spawn one at a time.
• Slimes never spawn on Peaceful, and mushroom fields have no slime spawns at all.

In swamps

Slimes can also spawn on the surface of swamps and mangrove swamps, between Y 51 and Y 69, where the light level is 7 or less. In Java Edition the moon matters: swamp slimes spawn most often at full moon and never at new moon. This kind of spawning has nothing to do with slime chunks, and the map does not show it.

How to find your seed

• Java singleplayer: type /seed in chat. It works even if cheats are off. Click the number in chat to copy it.
• Java server: /seed needs permission level 2 (operator). If you are not an operator, ask the server owner, who can run /seed from the console.
• Bedrock: the seed is on the Edit world screen, but you can skip it: Bedrock slime chunks do not depend on the seed.

If you typed text as the seed when you created a Java world, the game turned it into a number. This finder does the same conversion, and the hint under the seed box shows the result. When in doubt, the number from /seed is always right.

How to check a slime chunk in game

1. In Java Edition press F3 + G to show chunk borders. The Chunk line on the F3 screen starts with the chunk coordinates of the chunk you are in, and they should match the finder.
2. In Bedrock, turn on Show Coordinates in the world settings and walk until both X and Z are inside the chunk's block ranges.
3. Dig down below Y 40 and clear a room that fills the whole chunk, at least three blocks tall. Light it up so other mobs cannot spawn.
4. Step back and wait. Slime chunk spawning is slow, so give it a few minutes before deciding the chunk is wrong.

Slime farm basics

• Choose a good spot. Two or more slime chunks next to each other give a bigger spawning area. Zoom out on the map to look for clusters.
• Build spawning platforms. Stack several floors inside the slime chunk below Y 40, each with at least 2½ blocks of clear space. Light them so only slimes spawn.
• Spawn-proof the area. Hostile mobs share one mob cap, so every zombie and skeleton in nearby caves takes a spot a slime could have used. Light up or fill in caves within 128 blocks of where you wait.
• Stand in the right place (Java). Mobs do not spawn within 24 blocks of a player, and hostile mobs more than 128 blocks away despawn instantly. Wait at a spot 24 to 128 blocks from every platform. In Bedrock the spawn range depends on your simulation distance, so test your AFK spot there.
• Kill and collect. Large slimes split into two to four medium slimes, and medium ones split into small ones. Only small slimes drop slimeballs. Magma blocks, wither roses or soul campfires on the floor kill them without losing drops; hoppers or a hopper minecart underneath collect the slimeballs. An iron golem placed in view lures slimes toward the kill area.

Planning storage for the drops? The stack calculator turns slimeball counts into stacks and chests, and the Nether portal calculator helps you set up a fast route between your base and the farm.