Level 14

Total Experience Required 24,425

Level 100 progress: 0.36%

This is roughly the same as:

Killing 41 people in Warzone, or...
Killing 42 people in Execution, or...
Killing 35 people in Wingman, or...
Scoring 8,724 points in Guardian, or...
Scoring 26,549 points in Annex, or...
Scoring 16,070 points in Submission.

Horde (TU4)

Completing 62 waves on Casual, or...
Completing 41 waves on Normal, or...
Completing 31 waves on Hardcore, or...
Completing 25 waves on Insane.

Or a combination of the above. Have fun!