Level 96

Total Experience Required 6,041,216

Level 100 progress: 88.51%

This is roughly the same as:

Killing 20,138 people in Warzone, or...
Killing 20,549 people in Execution, or...
Killing 17,066 people in Wingman, or...
Scoring 4,315,155 points in Guardian, or...
Scoring 13,133,079 points in Annex, or...
Scoring 7,948,969 points in Submission.

Horde (TU4)

Completing 30,207 waves on Casual, or...
Completing 20,138 waves on Normal, or...
Completing 15,104 waves on Hardcore, or...
Completing 12,083 waves on Insane.

Or a combination of the above. Have fun!