Level 86

Total Experience Required 4,236,742

Level 100 progress: 62.07%

This is roughly the same as:

Killing 7,062 people in Warzone, or...
Killing 7,206 people in Execution, or...
Killing 5,985 people in Wingman, or...
Scoring 1,513,123 points in Guardian, or...
Scoring 4,605,155 points in Annex, or...
Scoring 2,787,331 points in Submission.

Horde (TU4)

Completing 10,592 waves on Casual, or...
Completing 7,062 waves on Normal, or...
Completing 5,296 waves on Hardcore, or...
Completing 4,237 waves on Insane.

Or a combination of the above. Have fun!