Level 49

Total Experience Required 583,954 [confirmed]

Level 100 progress: 8.56%

This is roughly:
Killing 1,947 people in Warzone, or...
Killing 1,987 people in Execution, or...
Killing 1,650 people in Wingman, or...
Scoring 417,110 points in Guardian, or...
Scoring 1,269,466 points in Annex, or...
Scoring 768,361 points in Submission.

Horde (TU4)

Completing 2,920 waves on Casual, or...
Completing 1,947 waves on Normal, or...
Completing 1,460 waves on Hardcore, or...
Completing 1,168 waves on Insane.

Or a combination of the above. Have fun!