What a mob spawner does and where to find one

A mob spawner is a block in Minecraft that automatically creates hostile mobs — zombies, skeletons, spiders, or creepers — in a small area around it. You do not build one from scratch. Instead, you find one in a dungeon, mineshaft, or stronghold, then modify it to farm mobs efficiently for drops like gunpowder, bones, or string.

Dungeons are the easiest source. They appear underground as small stone rooms with a spawner cage in the center, usually surrounded by chests. Mineshafts (the wooden tunnel networks you find deep underground) contain spawners too. Strongholds, which lead to the End dimension, have spawners in their corridors. Once you locate one, you can dig it out with a pickaxe and move it, or build your farm around it where it sits.

The spawner itself looks like a dark metal cage with a glowing core. Mobs appear inside it and walk out through the bars. The spawner only works if you are within 16 blocks of it horizontally and 8 blocks vertically — if you move too far away, it stops spawning.

Key Takeaways

  • Mob spawners are found in dungeons, mineshafts, and strongholds; you cannot craft them in survival mode.
  • The spawner only works when you are within 16 blocks horizontally and 8 blocks vertically, so your farm must keep you close enough.
  • Mobs spawn in a 9×9×9 cube centered on the spawner, so you need to clear that space and funnel mobs downward into a killing chamber.
  • Water channels, fall damage, and suffocation are the three main ways to kill mobs automatically without using weapons.
  • The spawner stops working if the light level around it rises above 7, so you must keep the spawning area dark.

Clearing the spawning chamber and controlling where mobs go

Once you find a spawner, dig out the 9×9×9 cube of blocks centered on it. This is the space where mobs actually appear. Remove all the stone and dirt, leaving just the spawner floating in an empty chamber. The mobs will spawn inside this empty space and when ready start walking around.

Next, dig a channel out of the spawning chamber — usually downward — to move mobs away from the spawner. Mobs follow basic pathfinding rules: they walk toward the nearest player or toward lower ground. A 2-block-wide, 2-block-tall tunnel works well. Line it with water flowing in one direction to push mobs along. Place water source blocks every other block so the current moves mobs steadily toward your killing chamber.

Keep the spawning area completely dark. Mobs only spawn when the light level is 7 or lower. If sunlight or torches reach the spawner, it stops working. Use dark oak wood or blackstone for walls if you want to see inside without breaking the darkness — these blocks look opaque even in low light.

Building a killing chamber with fall damage

The simplest killing chamber uses fall damage. At the end of your water channel, dig a shaft straight down — 20 to 30 blocks is enough to kill most mobs. The water pushes mobs off the edge, they fall, and they take damage. At the bottom, they land on solid ground or in more water.

Once mobs hit the ground after the fall, they have low health. You can finish them with a sword, or you can add a second layer: a 2-block drop onto suffocation blocks. Place a solid block (like sand or gravel) one block above the ground, then dig out the space underneath. Mobs fall onto the block, get pushed into the block above them, and suffocate. This kills them without you lifting a finger.

Collect the drops in a hopper at the bottom. A hopper is a block that sucks up items in a 1-block radius and moves them into a chest or another hopper below it. Place it under the killing zone and connect it to a chest with a hopper chain.

Using water and suffocation instead of fall damage

If you do not want to dig a deep shaft, you can kill mobs with water and suffocation alone. Dig a 1-block-wide channel and fill it with water flowing downward. Mobs walk into the water and get pushed down. At the bottom, place a solid block one block above the ground with the space underneath cleared. Mobs fall onto the block, suffocate against the block above, and die.

This method is slower than fall damage but uses less vertical space. It also works in any direction — you can run the water channel horizontally and then drop it down at the end, giving you more control over where your farm sits.

Lighting and safety around your spawner farm

Keep the spawning chamber dark, but light up the rest of your farm so mobs do not spawn in the tunnels or killing chamber. Place torches or lanterns in the water channels and around the hopper area. Mobs will not spawn in lit areas, so they stay confined to the spawner itself.

Build walls around your farm so mobs cannot escape into the wider world. A 3-block-high wall is enough — mobs cannot jump higher than that. Leave the top open if you want, or cover it with slabs to prevent mobs from spawning on top.

Stand at least 24 blocks away from the spawner when you want it to stop working temporarily. This is useful if you need to repair the farm or collect drops without mobs spawning. Move back within 16 blocks to restart it.

Connecting multiple spawners for a larger farm

If you find more than one spawner, you can connect them to the same killing chamber. Dig channels from each spawner toward a central point, then merge the channels into one shaft or water stream. This doubles or triples your mob output without building three separate farms.

Make sure each spawning chamber is dark and each channel has water flowing toward the center. The killing chamber stays the same — one suffocation block or fall shaft handles mobs from all sources.

Frequently Asked Questions

Can I move a spawner block to a different location?

In survival mode, no — spawners break when you mine them and drop nothing. In creative mode, you can pick them up. If you want a spawner in a specific location, you must build your farm around the spawner where you found it.

Why did my spawner stop working?

The most common reasons are: you are too far away (more than 16 blocks horizontally or 8 blocks vertically), the light level is too high (above 7), or there are too many mobs already spawned nearby (the spawner pauses if 6 or more mobs of that type are in the area). Move closer, add dark blocks, or kill the mobs around it.

Do I need to be actively playing to get drops?

Yes. The spawner only works when you are within range. If you log off or move far away, spawning stops and drops stop accumulating. You must stay near the farm for it to produce.

What is the best mob to farm?

Zombie and skeleton spawners are most common and drop useful items like rotten flesh and bones. Creeper spawners are valuable for gunpowder. Spider spawners drop string. The best choice depends on what you need and which spawner you find first.

Can I use a spawner farm on a multiplayer server?

Yes, but only the player within range of the spawner counts toward the 6-mob limit. If two players are near the same spawner, it may pause more often because both players' nearby mobs count. Larger farms with more killing capacity handle this better.