What a mob spawner does and where to find one

A mob spawner is a block in Minecraft that automatically creates hostile or passive creatures in a set area around it. You do not craft one — you find them in the world. Spawners appear naturally in dungeons (small underground rooms with stone brick walls), mineshafts, strongholds, and nether fortresses. Each spawner is already set to spawn one type of mob: zombies in dungeons, cave spiders in mineshafts, blazes in nether fortresses.

When you find a spawner, it looks like a cage made of iron bars with a glowing creature rotating inside. The spawner will begin creating mobs the moment you get within 16 blocks of it, and it will keep spawning them until you either destroy the block or move far enough away. Most players dig out the spawner and move it to a location where they want a farm — usually somewhere they can collect the drops (experience points, loot) safely.

Key Takeaways

  • Mob spawners are found naturally in dungeons, mineshafes, strongholds, and nether fortresses — you cannot craft them.
  • A spawner creates mobs in a roughly 9-block radius around it, so the room you build must be at least that size to work properly.
  • Mobs will not spawn if the light level is too high, so you need to keep your spawner room dark or use a spawner in the nether where light rules are different.
  • The fastest way to collect drops is to build a fall trap below the spawner that damages mobs without killing them, then finish them off with one hit to get experience.
  • You can move a spawner by mining it with a pickaxe, but it will only drop as an item if you use a pickaxe enchanted with Silk Touch.

Mining and moving a spawner to your farm location

To take a spawner from its original location, you need a pickaxe with the Silk Touch enchantment. A regular pickaxe will break the spawner but leave nothing behind. Silk Touch is an enchantment you add to a pickaxe at an enchanting table using lapis lazuli and experience points, or you can find it on pickaxes in loot chests. Once you have the pickaxe, mine the spawner block itself — not the iron bars around it — and it will drop as an item you can carry.

Transport the spawner to the location where you want to build your farm. Place it on the ground or suspended in the air — the spawner itself does not care about its height. The spawner will set up and begin creating mobs as soon as you place it, so have your farm structure ready before you place the block. If you place it too early, mobs will spawn in an uncontrolled way and you will waste time fighting them.

Building the room around your spawner

Mobs spawn in a roughly 9-block radius around the spawner block in all directions (up, down, left, right, forward, back). Build a room that is at least 11 blocks wide and 11 blocks long to give yourself room to work. The height depends on what you are building, but most farms use a tall room so mobs fall a distance that damages them without killing them outright.

The spawner itself does not care what blocks surround it, but the mobs it creates do. Most mobs will not spawn if the light level is higher than 7. In the overworld, this means you need to either keep the room completely dark (using no light sources) or use only very dim light like a single torch in a corner. In the nether, mobs spawn regardless of light level, so a nether spawner farm is easier to light and work in. Leave the spawner block itself exposed — do not cover it with other blocks.

Creating a drop system to collect mobs

The most efficient farm design uses a fall trap. Build a platform around the spawner at a height where mobs will spawn on it. Mobs will wander off the edge and fall into a pit below. The pit should be deep enough to damage the mobs significantly — usually 20 to 30 blocks — but not so deep that they die from the fall alone. You want them to survive with low health so you can hit them once and get the experience points.

At the bottom of the pit, create a small chamber where the damaged mobs collect. You can stand in this chamber and hit each mob once to finish it off. The mobs will drop experience orbs and their loot (bones, arrows, rotten flesh, gunpowder, etc.) into the same space. Use water channels to push the drops toward a collection point if you want to automate the process further, though this requires redstone knowledge beyond basic spawner building.

Lighting and mob behavior around your spawner

Mobs will only spawn on solid blocks in the dark. If you light your spawner room above light level 7, spawning will stop completely. This creates a problem: you need to see what you are doing, but you also need darkness for mobs to appear. Most players solve this by using a single torch or lantern placed far from the spawner, or by using a torch only when they are actively working on the farm and removing it when the farm is running.

Mobs also will not spawn if a player is standing directly on the spawning platform. This is why most farms have the player standing below or to the side of the spawning area. Mobs need an empty block to spawn into — if a block is occupied by a player, another mob, or a solid object, that spot will not generate a new mob.

Differences between overworld and nether spawners

Overworld spawners (from dungeons, mineshafts, and strongholds) require darkness to function. Nether spawners (from nether fortresses) spawn mobs regardless of light level, which makes them much easier to work with. You can light a nether spawner farm as brightly as you want and mobs will still appear. Nether spawners also spawn blazes, which drop blaze rods — a valuable resource for brewing potions and reaching the end dimension.

The trade-off is that nether spawners are harder to reach. You need to travel to the nether, find a fortress, locate the spawner inside it, and then either build your farm in the nether or transport the spawner back through a nether portal. Overworld spawners are usually easier to access, but the darkness requirement makes them more annoying to work with once you have built the farm.

Common mistakes that stop your spawner from working

The most common problem is light. If your spawner is not creating mobs, check the light level in the room using the debug screen (F3 on Java Edition). If it shows a light level above 7, add darkness. The second most common problem is distance. If you are more than 128 blocks away from the spawner, it will not spawn mobs at all. If you are between 32 and 128 blocks away, spawning slows down significantly. Stand close to your spawner farm for it to work at full speed.

A third problem is obstruction. If the spawning platform is covered with blocks or filled with other mobs, new mobs cannot spawn. Make sure the platform where mobs appear is clear and empty. Finally, check that you actually placed a spawner and not just iron bars. Iron bars look similar to a spawner cage but will not create any mobs. The spawner block itself has a glowing creature visible inside it.

Frequently Asked Questions

Can I move a spawner without Silk Touch?

No. A pickaxe without Silk Touch will break the spawner block and leave nothing behind. You must use a pickaxe with Silk Touch to pick up the spawner as an item. If you do not have Silk Touch, you can find it on pickaxes in loot chests or add it to a pickaxe at an enchanting table.

Why are no mobs spawning in my farm?

Check three things: light level (must be 7 or lower in the overworld), distance (you must be within 128 blocks, ideally within 32), and obstruction (the spawning platform must be empty). If all three are correct and mobs still are not appearing, verify you placed an actual spawner block and not just iron bars.

Do I need to be in the same chunk as the spawner for it to work?

No, but you need to be within 128 blocks of it. The spawner will not function if you are more than 128 blocks away. Spawning is fastest when you are within 16 blocks, so standing directly next to your farm is ideal for testing and collecting drops.

Can I use a spawner from the nether in the overworld?

Yes. Once you move a nether spawner to the overworld, it will follow overworld rules — it will only spawn mobs in darkness. A blaze spawner moved to the overworld will need a dark room to function, even though it spawned freely in the nether.

What is the best mob to farm?

Zombie and skeleton spawners are easiest because they drop useful items (rotten flesh, bones, arrows) and are common in dungeons. Blaze spawners are valuable because blaze rods are required for brewing and reaching the end dimension, but they are only found in nether fortresses. Cave spider spawners are generally avoided because cave spiders are small and hard to trap effectively.