The rank you achieve on Halo 3 multiplayer is dependent upon your experience and skill, and you can see what is required to attain each level below.

1. Recruit: Skill: 0, EXP: 1
2. Apprentice: Skill: 0, EXP: 2
3. Apprentice Grade 2: Skill: 0, EXP: 3
4. Private: Skill: 0, EXP: 5
5. Private Grade 2: Skill: 0, EXP: 7
6. Corporal: Skill: 0, EXP: 10
7. Corporal Grade 2: Skill: 0, EXP: 15
8. Sergeant: Skill: 0, EXP: 20
9. Sergeant Grade 2: Skill: 0, EXP: 30
10. Sergeant Grade 3: Skill: 0, EXP: 40
11. Gunnery Sergeant: Skill: 0, EXP: 50
12. Gunnery Sergeant Grade 2: Skill: 0, EXP: 60
13. Gunnery Sergeant Grade 3: Skill: 0, EXP: 150
14. Gunnery Sergeant Grade 4: Skill: 0, EXP: 300
15. Lieutenant: Skill: 10, EXP: 70
16. Lieutenant Grade 2: Skill: 10, EXP: 85
17. Lieutenant Grade 3: Skill: 10, EXP: 200
18. Lieutenant Grade 4: Skill: 10, EXP: 400
19. Captain: Skill: 20, EXP: 100
20. Captain Grade 2: Skill: 20, EXP: 150
21. Captain Grade 3: Skill: 20, EXP: 300
21. Captain Grade 4: Skill: 20, EXP: 600
22. Major: Skill: 30, EXP: 200
23. Major Grade 2: Skill: 30, EXP: 300
24. Major Grade 3: Skill: 30, EXP: 600
25. Major Grade 4: Skill: 30, EXP: 1,200
26. Commander: Skill: 35, EXP: 300
27. Commander Grade 2: Skill: 35, EXP: 450
28. Commander Grade 3: Skill: 35, EXP: 900
29. Commander Grade 4: Skill: 35, EXP: 1,800
30. Colonel: Skill: 40, EXP: 400
31. Colonel Grade 2: Skill: 40, EXP: 600
32. Colonel Grade 3: Skill: 40, EXP: 1,200
33. Colonel Grade 4: Skill: 40, EXP: 1,800
34. Brigadier: Skill: 45, EXP: 500
35. Brigadier Grade 2: Skill: 45, EXP: 1,000
36. Brigadier Grade 3: Skill: 45, EXP: 2,000
37. Brigadier Grade 4: Skill: 45, EXP: 4,000
38. General: Skill: 50, EXP: 600
39. General Grade 2: Skill: 50, EXP: 1,200
40. General Grade 3: Skill: 50, EXP: 2,500
41. General Grade 4: Skill: 50, EXP: 5,000