Minecraft wiki entry for Beginner%27s_guide, associated text: The power of torches has been sharply increased in recent versions of the game; as of version 1.18, they will completely prevent monsters from spawning (naturally) anywhere within reach of their light. This light stretches for 13 spaces of taxicab distance; each square east, west, north south, up, and down, counts independently. This if you have a torch at head height at one corner of a large room, the safe area will stretch 6 spaces diagonally on the floor (one space downward from the torch). On a hill, the light can stretch 4 blocks diagonally and up- or down-hill. Most solid blocks will also block light -- light can often travel around blocks, but any detour counts against its range.