Minecraft Light Levels Explained (Mob Spawns, Crops and Every Light Source)

Guide Java Bedrock

Quick answer: Light runs from 0 to 15. Overworld hostile mobs spawn only at block light 0, crops need light 9 or higher to grow, and ice melts at light 12+. Torches give 14, lanterns and glowstone 15, soul torches 10, redstone torches 7 - press F3 (Java) to see the light level at your feet.

What you need

Torches or better for spawn-proofing
F3 debug screen on Java (light level reads at your position)
Any 15-light source for max brightness

Step by step

The spawn rule: hostile mobs in the Overworld need a block light of exactly 0 (and a sky light of 7 or less), so any light source nearby stops spawns on the blocks it reaches.
Light falls by 1 for every block of distance from the source, counting steps along each axis. A torch (14) still gives some light 13 blocks away in a straight line; space torches so no dark gaps remain between them.
Level 15 sources: glowstone, sea lantern, shroomlight, lantern, campfire, jack o'lantern, lava, beacon, conduit, froglights, crying obsidian is 10 (not 15) - check before you build with it.
Torch 14, end rod 14; soul torch and soul lantern 10; redstone torch 7; candles 3 per candle up to 12; magma 3.
Crops: farmland crops need light 9+ to grow - torches over the rows double as decoration and night farming.
Snow and ice: ice melts at block light 12+ from non-sun sources - keep lanterns away from ice paths; sunlight never melts ice.
Reading light: on Java press F3 and look for 'Client Light' (block + sky). On Bedrock, enable the light level overlay in video settings or count torch distance.
Skylight vs block light: mobs care about internal light combining both - underground, only your placed block light matters, which is why caves need torches even at noon.

Java vs Bedrock

Light source values are the same on both editions. Block-light rules for mob spawning are described for Java in this guide; Bedrock differs in details such as light-filtering blocks and passive mob spawning, so check in-game before relying on exact spacing.

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

Frequently asked questions

What light level do mobs spawn at?

Overworld hostile mobs need block light 0 and sky light 7 or less. Any light source that reaches a block stops them from spawning there.

How do I see light levels?

Java: press F3 and read the light value at your position. Bedrock: turn on the light level overlay in video settings (or use the F3-style debug on some devices).

Do mobs spawn on slabs and glass?

Light aside, mobs cannot spawn on bottom slabs, glass, leaves or carpets - a cheap way to spawn-proof dark corners without lighting them.