How to Get Wither Skeleton Skulls in Minecraft

Guide Java Bedrock

Quick answer: Wither skeleton skulls only drop from wither skeletons, which are found exclusively in nether fortresses. The drop chance is 2.5% per kill. Each Looting level adds 1% in Java (5.5% at Looting III) and 2% in Bedrock (8.5% at Looting III). You need 3 skulls to summon the Wither.

What you need

A sword with Looting III
Food and milk (wither skeletons inflict the Wither effect)
A shield and armor

Step by step

Find a nether fortress: wither skeletons spawn only there, at light level 0 to 7. In Java they spawn in groups of 5, in Bedrock in groups of 2-3.
Know where they spawn: inside the bounding box of any single fortress piece they spawn on any block; in the wider fortress area only on nether bricks.
Use a sword with Looting: the skull chance is 2.5% by default. In Java it is 3.5%, 4.5% and 5.5% with Looting I, II and III; in Bedrock it is 4.5%, 6.5% and 8.5%.
Kill them yourself. The skull drops only when a player kills the wither skeleton (in Java a tamed wolf also counts).
A wither skeleton killed by a charged creeper also drops its skull.
Expect a grind: at 2.5% the average is 40 kills per skull, and at 5.5% (Java, Looting III) about 18, or about 12 at 8.5% (Bedrock, Looting III). Wither skeletons inflict the Wither effect, and drinking milk cures it.
Wither skeletons also drop coal and bones, and they are the only renewable source of coal.

Java vs Bedrock

Java wither skeletons spawn in groups of 5, Bedrock in groups of 2-3. In Java a tamed wolf's kill also drops a skull; the Bedrock table lists only player kills. The Wither itself spawns 3-4 wither skeletons below half health on Normal and Hard.

Versions: Describes the current Java and Bedrock releases. See the edition note above for differences.

Frequently asked questions

What is the drop rate for wither skeleton skulls?

2.5% with no Looting. Java: 3.5% with Looting I, 4.5% with Looting II and 5.5% with Looting III. Bedrock: 4.5%, 6.5% and 8.5%.

Where do wither skeletons spawn?

Only in nether fortresses, at light level 0 to 7. Inside a fortress piece's bounding box they spawn on any block; elsewhere in the fortress area only on nether bricks.

How many kills do I need for 3 skulls?

On average 40 kills per skull at 2.5% (about 120 for three). With Looting III that drops to about 18 per skull in Java (5.5%, about 55 for three) or about 12 in Bedrock (8.5%, about 35 for three). It is chance, so it can take more or fewer.

Can a charged creeper get me a skull?

Yes. A wither skeleton killed by a charged creeper drops its skull.