Minecraft Forums

Taken directly from the Minecraft wiki:
"When the player dies, they only drop half of their experience as orbs, rounded down to the nearest point. The other half vanishes."

Just died to a swarm of endermen, with 13 levels on me. I respawn at my bed, and run back to the spot. Everything's there.
Except after picking up the XP orbs, guess what? Less than 2/3 of level 1.
I'ma call BS on the wiki.

Last time I tried it, I had 6 levels, plus about 80% on the meter. When I died and picked up the orbs, I had the 6 levels, but not the 80% from the meter.

I think its 1/2 of the experice you have... but all the levels are lost

Sometimes i get all levels, and sometimes i get like nothing. random much?

I had over 8300 levels once (quite obviously cheated in) then I died, and only got 300~ back.

I died with only a few levels on me in a random tester world and when I went back to get my stuff, got all of my levels back, but no experience.

I died once with 5 levels,and when I picked up the XP I had 7.