When you mouse over the experience bar right below your portrait in game, the tooltip says "Exp need to next lvl XXX" where XXX is a number.
I killed a bandit camp and the bar filled up more but the XXX number went from 1515 to 1533.
Bandit camp had 10 of the low level bandits (German forum says they give 2 exp per unit killed so I lost two experience I should have gotten if that is correct).
those numbers imply the tool tip is showing current experience and not experience needed for next level.
Attached is a screen shot of the tool tip. I have since killed another bandit camp and confirmed that i am getting 2 exp per bandit killed but tool tip keeps showing higher numbers.