Slime Chunk Finder & Visualizer

Complete Slime Chunk Guide

How Slime Chunks Work

In Minecraft Java Edition, slimes spawn in specific chunks called "slime chunks" below Y=40, regardless of light level. These chunks are determined purely by the world seed using a deterministic algorithm. Approximately 10% of all chunks are slime chunks.

This tool uses the exact same algorithm as Minecraft, meaning the results are 100% accurate for your seed. The calculation happens entirely in your browser - no data is sent to any server.

Building an Efficient Slime Farm

Location Selection

• Find clusters: Enable "Show Clusters" to find groups of adjacent slime chunks. Larger clusters = more spawning space.
• Check simulation distance: Yellow highlighting shows chunks within your sim distance setting. Slimes won't spawn outside this range.
• Minimize cave interference: Choose locations where you can easily light up or spawn-proof nearby caves to maximize slime spawns.
• Accessibility: Build near your base or create good transportation (nether portal, ice boats, etc.).

Farm Construction

• Y-level range: Slimes spawn from Y=0 to Y=39 in slime chunks. Clear this entire range or build multiple platforms.
• Platform spacing: Space platforms 3-4 blocks apart vertically to maximize spawning layers.
• Chunk boundaries: Stay within the chunk! The tool shows you exact block coordinates (X: 0-15, Z: 0-15 within each chunk).
• Spawning pads: Use the "Platform Points" suggestion for a 12×12 interior grid, leaving 2-block margins from chunk edges.
• Collection system: Add water streams, trapdoors, or iron golems to push/kill slimes toward a collection point.

Spawn Requirements

• Must be in a slime chunk (shown in green on the map)
• Y-level below 40 (typically Y=0 to Y=39)
• Minimum 2.04×2.04×2.04 block space for spawning
• Light level can be anything (unlike most mobs)
• Player within simulation distance
• Not too close to player (24+ blocks away)

Using This Tool Effectively

Getting Your Seed

• Java Edition: Type /seed in chat (requires cheats or operator permissions)
• Single Player: Open world to LAN with cheats, then use /seed
• String seeds: Enter text seeds (they'll be hashed automatically)

Navigation Tips

• F3 coordinates: Press F3 in-game, copy your position, then paste in the "F3 Coordinates" box and click Parse.
• Quick spawn: Click "Spawn (0, 0)" to center the view on world spawn.
• Center on chunk: Select any chunk, then click "Center Selected" to zoom in on that area.
• Share your map: Click "Share Link" to get a URL with all your settings - perfect for planning with friends.

Advanced Features

• BigInt Mode: For extreme coordinates beyond ±16 million blocks, enable this for perfect accuracy.
• Cluster Analysis: Shows the largest group of connected slime chunks - ideal for mega-farms.
• Swamp Overlay: Paste swamp biome chunk coordinates to visualize dual slime/swamp farm opportunities.
• Adjacent Counter: Select a slime chunk to see how many neighboring chunks are also slime chunks (shows as "+1", "+2", etc).

Optimization Strategies

Maximize Rates

1. Light up all caves within 128 blocks to force spawns in your farm
2. Build in multiple adjacent slime chunks (check the "+X" indicator)
3. Stack platforms to maximize spawning surface area
4. AFK spot should be 24-32 blocks from nearest spawning platform
5. Keep farm centered in your simulation distance circle

Multi-Chunk Farms

When you select a slime chunk, look at the "Adjacent Slime Chunks" count. A chunk with 2+ adjacent slime chunks is excellent for building larger farms. The tool highlights these connections on the grid.

Common Questions

Why aren't slimes spawning in my farm?

• Verify you're in the correct chunk coordinates (check both X and Z ranges)
• Ensure farm is below Y=40
• Check that you're within simulation distance (default is 10 chunks)
• Light up nearby caves - slimes compete with other mobs for the mob cap
• Make sure platforms have enough space (at least 2×2×2 minimum)

Do slime chunks work in all game versions?

This algorithm is accurate for modern Java Edition (1.4+). The slime chunk formula has been stable since 2012. Bedrock Edition uses a different system entirely.

Can I use this for multiplayer servers?

Yes! Just get the world seed from a server operator. All players on the same seed will have identical slime chunks. Use the "Share Link" feature to coordinate farm locations with teammates.

What about swamp slime spawning?

Swamp slimes spawn on the surface in swamp biomes at night with specific light levels (≤7) during certain moon phases. This is independent of slime chunks. You can use the Swamp Overlay feature to mark swamp biomes and potentially build dual-purpose farms in chunks that are both swamp biome AND slime chunks.

Technical Details

This tool implements the exact Minecraft Java Edition algorithm:

new Random(
  seed +
  (chunkX * chunkX * 4987142L) +
  (chunkX * 5947611L) +
  (chunkZ * chunkZ * 4392871L) +
  (chunkZ * 389711L) ^ 987234911L
).nextInt(10) == 0

A chunk is a slime chunk if this formula returns 0. The calculation uses Java's Linear Congruential Generator (LCG) with 48-bit state, exactly matching the game's random number generation. This has been verified through decompilation and testing across millions of seeds.