Breaking Bedrock | Technical Minecraft Wikia | Fandom
This is a list of all types of bedrock:a. The bottom of the overworld and nether, y-levels 0 to 4. Layer 0 is 100% bedrock, and each subsequent layer contains 20% less than the last, so y-4 is only 20% bedrock. This is the same on every seed. The roof of the nether, y-levels 122 to 127.