Minecraft wiki entry for Before_1.8, associated text: Example: Say we have a sword with Sharpness 3, Knockback 2 and Looting 2. Referring to the table we see that the Enchantments will cost 3×1 → 3, 2×2 → 4, and 2×4 → 8 respectively, and another 6 levels for having three of them. 3+4+8+6 → 21. In the anvil for the first time, this sword will cost at least 21 levels to work on, even before considering what to do with it.