Level 46

Total Experience Required 473,201 [confirmed]

Level 100 progress: 6.93%

This is roughly:
Killing 1,578 people in Warzone, or...
Killing 1,610 people in Execution, or...
Killing 1,337 people in Wingman, or...
Scoring 338,001 points in Guardian, or...
Scoring 1,028,698 points in Annex, or...
Scoring 622,633 points in Submission.

Horde (TU4)

Completing 2,367 waves on Casual, or...
Completing 1,578 waves on Normal, or...
Completing 1,184 waves on Hardcore, or...
Completing 947 waves on Insane.

Or a combination of the above. Have fun!