XP per kill
Heroes go from level 1 to level 70. The XP needed per level rises from 200 at level 1 to 37,253,545 at level 69; reaching level 70 takes 549,158,616 XP in all. After that, XP goes to Paragon levels.
Formula
An enemy gives XP once, when it dies. Base XP = its base health x (1 + 0.1 for every enemy level above 1), rounded, at least 1. XP = base XP x the level factor x (1 + XP Gained) x the difficulty's XP multiplier, rounded, at least 1. Rounding goes to the nearest whole number, halves to the even one. An enemy with 100 base health at level 1 gives 100 XP on Normal.
The base health is the enemy's own, as on its page: on Nightmare and Inferno its Nightmare and Inferno base health where it has one, and every enemy outside the Mythic Rift is level 70 there. The health multipliers for level, elites, difficulty and rift tier do not count, so an elite gives the same XP as a normal enemy of its type and level. For online characters, an enemy with XP planned by the game server gives that XP instead.
Level, difficulty and Paragon
Full XP while the hero's level is at or below the enemy's level, 1/6 less for each level above it. From 6 levels above the factor is 0, but a kill still gives 1 XP: no kill gives 0 XP, so every kill also gives each ability in the hero's 4 slots 1 ability XP. XP column: an enemy with a base XP of 600.
| Hero levels above | Share | XP |
|---|---|---|
| 0 or below | 6/6 (100%) | 600 |
| 1 | 5/6 (83.33%) | 500 |
| 2 | 4/6 (66.67%) | 400 |
| 3 | 3/6 (50%) | 300 |
| 4 | 2/6 (33.33%) | 200 |
| 5 | 1/6 (16.67%) | 100 |
| 6 or more | 0 | 1 |
XP multiplier: x1 on Normal, x1.5 on Nightmare, x2 on Inferno. In the Mythic Rift (Inferno, level 70) it is x2 + 0.015 per tier: x2.015 at tier 1, x3.5 at tier 100. A rift enemy's base health is 30 x its rift size (1, 2 or 3), the boss's 5,000; XP per kill with the hero at level 70 and no XP Gained:
| Tier | Size 1 / 2 / 3 | Boss |
|---|---|---|
| 1 | 478 / 955 / 1,433 | 79,593 |
| 25 | 563 / 1,126 / 1,689 | 93,812 |
| 50 | 652 / 1,304 / 1,955 | 108,625 |
| 75 | 741 / 1,481 / 2,222 | 123,438 |
| 100 | 830 / 1,659 / 2,488 | 138,250 |
At level 70 all kill XP goes to Paragon XP, with 70 as the hero's level in the level factor. A kill that brings the hero to level 70 sends the XP left over to Paragon.