Level 28

Total Experience Required 109,938

Level 100 progress: 1.61%

This is roughly the same as:

Killing 184 people in Warzone, or...
Killing 187 people in Execution, or...
Killing 156 people in Wingman, or...
Scoring 39,264 points in Guardian, or...
Scoring 119,498 points in Annex, or...
Scoring 72,328 points in Submission.

Horde (TU4)

Completing 275 waves on Casual, or...
Completing 184 waves on Normal, or...
Completing 138 waves on Hardcore, or...
Completing 110 waves on Insane.

Or a combination of the above. Have fun!