Ok, I'll go and check for you.
.............(checking)................... Found it!
You have an experience cap on 2950000 points. And here comes a list on how many levels you can reach:
- Fighter: 19
Paladin: 17
Ranger: 17
Wizard: 17
Cleric: 21
Druid: 14
Thief: 23
Bard: 23
Sorcerer: 17
Monk: 21
Barbarian: 19
This counts for all races.
see ya!