At every level from 1st to 11th, the experience needed to reach the next level (from the current level) increases every level. However, this pattern gets broken for most of the later levels:
- Going from 10th to 11th takes 21,000xp (= 85k – 64k), but 11th to 12th takes only 15,000xp! (= 100k – 85k).
- Both 13th and 14th level only take extra 20k experience each, i.e. the amount needed doesn't increase between those two levels.
- Levels 16 and 17 similarly only need 30k experience each, and 18 and 19 only need 40k experience each.
Why does the last half of the experience chart have some of these levels maintain the same experience costs, and even briefly decrease the experience cost for 12th level?
Best Answer
First, I don't believe that "why" is something that this community can answer; this was a decision of the designers and their reasons, to the extent that they have any, are a mystery.
Notwithstanding, your question is why the XP per level looks like this:
Steady growth until 11th level, then a sharp drop and not reaching the 10->11 level again until 14->15.
However, the XP values are only one side of the equation; the other is how much XP is gained per encounter (p.82 DMG). Ignoring modifiers, by combining these you get this chart:
Easy, Hard and Deadly encounters are approximately 2/3, 1.5 and 3 times a Medium encounter (presumably because of rounding off). Focusing just on the "Medium" encounters (which should be the bulk of encounters) it can be seen that you need 6 to reach levels 2 and 3, 12 to reach 4, approximately 15 for levels 5 through 10, 17 for level 11 and then about 9 to 10 for levels 12 to 20.
However, due to the strange way that XP budgets do not equate with XP awarded, you will only have this number of encounters if every encounter is with a single monster. If your encounters are typically with 3-6 creatures (most of mine are) then you will need twice as many encounters to get the same number of XP.
In this context, the jump at level 11 is only about 10% and then it falls to a much lower and approximately constant value.
If I were to speculate, and I will, I would guess that the design intent is to:
This accelerates the PCs through the fragile early stages and provides rapid gratification, provides a long period of play in the mid-levels, suitable for the dungeon-grind and then move more quickly through the levels where nation and world shaking events may be happening.