Minecraft wiki entry for Charcoal, associated text: When used in a furnace as a fuel, a piece of charcoal lasts 80 seconds (smelting up to 8 items), the same as coal. Charcoal used as fuel lasts more than 5 times longer than wood planks or wood logs used as fuel, being more efficient than any other use of wood for smelting in Java Edition, but outstripped by wooden slabs in Bedrock.