what are the chances of a nether fortress of spawning

Nether fortresses have a 40% chance of generating in Java Edition and about 33.3% in Bedrock Edition, based on the source results gathered here.

Quick Scoop

• Java Edition: roughly 40% chance for a fortress to generate in a given Nether region.

• Bedrock Edition: roughly 33.3% chance.

• They generate in all Nether biomes , so biome choice does not prevent one from appearing.

What that means

That does not mean every portal area gets a fortress nearby, only that the world generation system gives fortresses a chance to appear as the Nether is divided into regions. The actual distance to the nearest fortress can still vary a lot from seed to seed, which is why some players find one quickly while others travel much farther.

Useful context

Nether fortresses matter because they are the only place where blazes and wither skeletons spawn, and they also contain nether wart and useful loot. That is why players often search for them early in survival worlds.

TL;DR: In Minecraft, Nether fortresses spawn with about a 40% chance in Java and 33.3% in Bedrock.