Minecraft wiki entry for Experience, associated text: The experience level costs were heavily revised in snapshot 12w22a and 12w23a, and again in version 1.8. Before these, reaching level 50 (the maximum usable on a single enchantment) required 4625 experience, corresponding to defeating 925 hostile mobs (assuming the "common" ones.) Afterward, considerably less experience is needed to get into higher levels. Higher levels cost more experience than lower ones, but the levels are still easier to get than in 1.2.5. Now, level 30 is the maximum for enchantments, and that cost is equivalent of 279 "common" enemies, less than 1/3 the old price.