How to Make a Creeper Farm in Minecraft

Guide Java Bedrock

Quick answer: A creeper farm spawns creepers in a dark room with a trapdoor ceiling - exactly short enough that zombies and skeletons cannot spawn but creepers can - then flushes them with water to a kill zone. Even a small one produces a steady supply of gunpowder for TNT and firework rockets.

What you need

Stacks of solid building blocks and trapdoors
Carpets (spider-proofing) and water buckets
Cats (tame ocelots... cats - in a village or swamp hut)
Campfires or a Looting III sword
Chests and hoppers for collection

Step by step

Pick the spot. Over an ocean is ideal: fewer caves below means almost every spawn happens inside your farm. On land, light up or slab every cave in range first, or rates collapse.
Build a dark spawning platform. Any solid blocks, completely dark inside, with a 2-block-high interior. Start with one layer about 8x8 and expand later - layers stack with 3 blocks of vertical space.
Add the trapdoor ceiling. Cover the ceiling with trapdoors so the effective height drops to 1 and 13/16 blocks. Creepers spawn in that space; zombies, skeletons and witches cannot. This trick is the whole farm.
Block the spiders. Spiders still fit under trapdoors. Place carpets on the floor with 2 empty blocks between them so no flat 3x3 area remains - spiders need that space and creepers do not.
Flush them out. Water streams push creepers to a central drop. To move them faster, place cats at the far end - creepers flee from cats and run straight into your water channel.
Kill for gunpowder. Campfires under the drop kill automatically and safely. For much better rates, drop them to half a heart and finish them with a Looting III sword.
AFK in the right place. Stand about 120 blocks above the farm on a platform so mobs spawn inside the farm but outside your 24-block no-spawn bubble. Check rates after 10 minutes and add layers if you want more.

Java vs Bedrock

The trapdoor height trick is Java-only: in Bedrock, creepers do not spawn under a 2-block trapdoor ceiling the same way, so Bedrock farms use other creeper-only layouts or accept mixed mobs with cat-scaring. Cat fleeing and campfire killing work on both.

Versions: Creeper farms grew up with the trapdoor ceiling trick in the early versions, and boat/minecart mob storage (1.16) later enabled charged-creeper factories for mob heads.

Frequently asked questions

Why is my creeper farm so slow?

Unlit caves and the surface around the farm eat your mob cap. Light up or slab everything in a 128-block sphere, or move the farm high over an ocean. Also make sure you AFK 24+ blocks from the platforms - mobs never spawn closer than that to you.

How do I get only creepers and no other mobs?

The trapdoor ceiling handles zombies and skeletons (Java), carpets spaced 2 apart handle spiders, and endermen cannot fit in a 2-high space anyway. What remains is creepers only.

Campfires or Looting III?

Campfires are fully automatic and safe - gunpowder survives the fire, unlike lava. Looting III by hand multiplies gunpowder several times over and also gives XP, but you have to stand there swinging. Most players build campfires first and add a manual mode later.