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Calculator

Furnace Fuel Calculator

One smelt takes 200 ticks, and every fuel burns for a fixed time — a lava bucket does 100 items, coal does 8, a plank does one and a half. Enter how many items you are smelting and this shows exactly how much of each fuel that takes, so you stop overshooting on charcoal or wasting a bucket of lava on half a stack.

Calculator
Furnace Fuel Calculator
Furnace time
10m 40s
FuelSmeltsNeed
Lava bucket1001
Block of coal801
Dried kelp block204
Blaze rod126
Coal88
Charcoal88
Bamboo block1.543
Any log or planks1.543
Wooden slab0.7586
Stick0.5128
Bamboo0.25256

One smelt takes 200 ticks (10s). Fuel burns whole units, so any leftover burn time on the last piece is wasted — a lava bucket poured into 1 item still costs the whole bucket.