What a mob spawner does and where to find one

A mob spawner is a block that automatically creates mobs (hostile creatures, animals, or other entities) in a set area around it. You cannot craft one — spawners only appear naturally in the world, usually in dungeons, mineshafts, strongholds, and other generated structures. When you find one, it sits in a cage of iron bars or stone brick and shows a spinning mob model inside.

The spawner you find will already be set to spawn one type of mob. A dungeon spawner might spawn zombies, skeletons, or spiders. A mineshaft spawner spawns cave spiders. A stronghold spawner spawns silverfish. You cannot change what type of mob a spawner creates without commands or a spawn egg (which you can only get in Creative mode or with commands in Survival).

Key Takeaways

  • Mob spawners spawn mobs in a roughly 8-block radius around them, but only if the light level is low enough and no player is watching.
  • You need to dig out a large chamber around the spawner, then build a collection system to funnel mobs into a killing area.
  • The spawner will not work if a player stands too close, so you must be at least 16 blocks away horizontally or the spawning stops.
  • Water channels, fall damage, and suffocation are the most common ways to kill mobs automatically once they spawn.
  • Torches, slabs, and carpet prevent mobs from spawning on certain blocks, which lets you control where they appear.

Clearing space and preparing the spawner chamber

Start by mining out a large cube around the spawner — at least 16 blocks in each direction from the spawner block itself. The spawner creates mobs in a sphere roughly 8 blocks away from its center, but you need extra room for water channels, killing mechanisms, and collection areas. Leave the spawner block itself untouched; breaking it will destroy it permanently in Survival mode.

Once you have cleared the space, light up the area with torches so mobs do not spawn while you are building. Place torches on the walls and floor, keeping the light level at 8 or higher everywhere except the spawning chamber itself. This prevents unwanted mobs from appearing while you work.

If the spawner is in a dungeon or mineshaft, you may need to clear out connecting tunnels and rooms so mobs do not wander away. Seal off doorways and passages with blocks or walls so all spawned mobs stay in your chamber.

Building a water collection system

Water is the easiest way to move mobs from the spawner to a killing area. Dig channels in the floor leading away from the spawner, then place water source blocks to create flowing water. The water will push mobs along the channel toward your collection point.

Make the channels 2 blocks wide and 1 block deep so mobs cannot escape sideways. The water should flow downward at the end of the channel, dropping mobs into a pit or chamber below. You can use a 2-block drop, a 20-block drop, or any height in between — the height determines how much damage mobs take when they land.

Test the water flow by standing away from the spawner (at least 16 blocks) and watching mobs spawn and move. They should follow the water toward the collection point. If mobs are getting stuck, widen the channel or add more water source blocks to increase the flow speed.

Choosing a killing method

Once mobs reach your collection chamber, you need a way to kill them. The most common methods are fall damage, suffocation, drowning, and fire. Each has trade-offs in terms of setup time and the drops you get.

Fall damage is simple: drop mobs 24 or more blocks and they die on impact. This works for most mobs but leaves them scattered across the floor. You will need to walk around collecting drops, or use a hopper system to gather them automatically.

Suffocation uses pistons to push mobs into a 1-block-tall space, crushing them. This is more complex to build but keeps drops in one place. Drowning works by trapping mobs in water with no air blocks nearby — they take damage over time and die. Fire kills mobs but may burn some drops, so it is less efficient for collecting loot.

Controlling where mobs spawn with blocks

Mobs can only spawn on solid blocks in dark areas. You can use this to your advantage by placing slabs, carpet, or stairs on the floor around the spawner. These blocks prevent mobs from spawning on them, so you can funnel all spawns to a specific area.

For example, place slabs on the floor everywhere except a 3-by-3 area directly below the spawner. All mobs will spawn in that small zone, making it easier to push them into your water channel. You can also use carpet on top of solid blocks to prevent spawning while keeping the floor walkable.

Torches and other light sources also prevent spawning. If you want mobs to spawn only in a dark chamber below, light up the area around the spawner with torches, then remove all light sources from the chamber below. Mobs will only spawn in the dark zone.

Staying far enough away so the spawner works

A spawner stops creating mobs if any player is within 16 blocks of it (measured horizontally, not counting vertical distance). This means you must stand at least 16 blocks away for spawning to continue. If you are too close, the spawner pauses.

Build an AFK platform (a safe spot where you can stand idle) at least 16 blocks away from the spawner. This is usually a small platform above or to the side of the spawner chamber, with walls or a roof to protect you from mobs. From there, you can watch the spawner work without stopping it.

If you want to be even further away, stand 32 blocks or more distant. At that range, mobs despawn if they wander too far from the spawner, which prevents your farm from getting overcrowded. This is useful for large spawner farms where you want steady output without lag.

Collecting drops automatically with hoppers

If you want to gather drops without walking around, use hoppers and chests. Place hoppers on the floor of your killing chamber, pointing into a chest or into more hoppers that lead to a central storage chest. Mobs that die on or near the hoppers will drop items, and the hoppers will pull those items into storage.

Hoppers work slowly — they pull one item every 0.4 seconds — so you may need multiple hoppers to keep up with a fast spawner. Space them out across the killing chamber so items do not pile up on the ground.

For a more compact setup, use a hopper minecart on rails running under the killing chamber. The minecart picks up items faster than stationary hoppers and can carry them to a distant storage area. This is more complex to build but much more efficient for large farms.

Frequently Asked Questions

Can I move a mob spawner to a different location?

No. Spawners cannot be moved in Survival mode — if you break one, it disappears. You can only use spawners where you find them naturally. In Creative mode, you can pick up a spawner with a pickaxe and place it elsewhere, but this does not work in Survival.

Why is my spawner not creating mobs?

The most common reasons are: you are standing too close (within 16 blocks), the area is too bright (light level above 8), or there are too many mobs already spawned nearby. Move away, add darkness, or kill the existing mobs. Also check that the spawner block itself is intact and not covered by another block.

Do I need to do anything special for cave spider spawners?

Cave spiders are smaller than regular spiders and can fit through 1-block gaps. Make sure your channels and collection chamber have solid walls with no cracks, or they will escape. Otherwise, treat them the same as any other spawner.

What is the best mob to farm with a spawner?

Zombie and skeleton spawners are most common and drop useful items like rotten flesh, bones, and armor. Blaze spawners in the Nether drop blaze rods, which are essential for brewing. Spider spawners drop string and spider eyes. The best choice depends on what you need most.

How many mobs will a spawner create per second?

A spawner creates mobs in waves, typically spawning 4 to 8 mobs at once, then waiting 10 to 40 seconds before the next wave. The exact timing varies based on how many mobs are already nearby. If you kill mobs quickly, the spawner will spawn more frequently.