XP

Experience Points (XP) are a numerical quantity exclusive to Multiplayer that dictates a player's level in and progress in that level. One's progress through an individual level is shown on the bottom of the screen by a yellow meter, though this feature is not included in Black Ops. When a player gains experience points, the meter moves further to right and resets when having achieved the next level.

Ranking through Experience Points is only available in Call of Duty 4: Modern Warfare, Call of Duty: World at War, Call of Duty: Modern Warfare 2, Call of Duty: Black Ops, and Call of Duty: Modern Warfare 3. Experience points are also available in Call of Duty: United Offensive but there is no experience meter and the ranks reset when one ends or exits a match.

Call of Duty: United Offensive
United Offensive was the first game to feature a pseudo-experience point system. Upon the start of each game, a player spawns as a Private with a limited amount of ammo and a single grenade. Points are accumulated from kills, flag captures, bunker destruction, and the like, with every ten points resulting in a promotion to a higher rank. Ranks and points do not carry on from game to game; they are reset for every game.

Call of Duty 4: Modern Warfare

 * Killing the enemy. The player gains 10 points per kill in Team Deathmatch (all forms) and Sabotage. 5 points are earned for killing in Free for All, Headquarters and Domination. The player can gain 50 points per kill in Search and Destroy, as no respawns are permitted; the life is worth more. Kills in Cage Matches are worth 20 points. If one kills when using Last Stand perk, double points will be earned. In Headquarters or Domination, a player can score an extra 5 experience points for killing an enemy who is within an objective capture range (i.e. within a Domination flag).


 * XP Stacking. The XP indicator will stack when earned in rapid succession. For example, if a player kills 3 people rapidly in Team Deathmatch (although this works in all modes), the player earns 10XP for every kill, and the XP that appears in the middle of the screen will continue counting past 10. Some players think that "XP stacking" means that the second kill would be worth 20 XP, and the third kill would be worth 30 XP, etc., but this is not the case.


 * Assisting in the death of an enemy. If the player injures an enemy but does not kill that enemy and that player dies before their health is fully regenerated the player is awarded an assist, 2 experience points for matches which grant 10 XP a kill, 1 for kills which grant 5 XP a kill, and 25 points in Search and Destroy. Assists are impossible to achieve in Free-for-all mode.


 * Completing challenges. Challenges are a new method to gain experience points. Challenges have some requirements to be fulfilled before the reward is available. For example, for Marksman challenges, one needs to kill the enemy using the pertinent gun. In Expert challenges, one would need to kill the enemy via headshots with the gun. There are also challenges that requires player to do other, more varied tasks. For example, the "think fast" challenge requires a player to kill an enemy by directly hitting the enemy with a Fragmentation Grenade. The challenges involving guns gives either attachments or camouflages as an addition to experience points. Other challenges give only experience points.


 * Additionally: The game gives some bonus points for the player's performance when the match ends as a "Match Bonus". The match bonus is based only on one's rank, the duration of the match and the gamemode. It does not, contrary to popular belief, include the amount of kills or deaths. So a player on the top of scoreboard can still get less match bonus than a person at the bottom.

Call of Duty: World at War
The player can gain experience points in the same manner as in Call of Duty 4: Modern Warfare, but also by:


 * Cooperative (Co-op) gameplay. This is a new mode where one can play the missions in normal gameplay but with 2-4 players. One can do exclusive challenges when playing in Co-op. Remember that in Co-op only the XP gained from Co-op challenges count for one's level, the XP earned in the Co-op missions for kills or objectives do not count. Playing Nazi Zombies does not gives any experience points. Playing in split screen cooperative mode also does not give any experience points


 * Completing vehicle challenges
 * Killing a dog: this gives 3 points in all game modes except Free for All (2 points) and Search and Destroy (not confirmed)


 * Reviving a teammate whom is using Second Chance. This gives the player 2 points.

For example in Team Deathmatch:
 * Gaining an assist. This is more complicated than Call of Duty 4: Modern Warfare as the amount of experience points gained is proportionate to the amount of damage inflicted towards the enemy. This is given in multiples of 5ths of the amount of XP given for a kill. The only exception is Search and Destroy, where all assists are worth 25 XP.
 * 10 points for a kill.
 * 2 assist points for at 1-39% of damage given.
 * 4 assist points for at 40-59% of damage given.
 * 6 assist points for at 60-79% of damage given.
 * 8 assist points for at 80-99% of damage given, includes putting an enemy in Second Chance with a teammate "stealing" the kill.

Call of Duty: Modern Warfare 2
The experience system in Call of Duty: Modern Warfare 2 contains many new additions. Instead of just receiving XP for kills and challenges, the player receives "medals" with each kill that will reward additional XP:


 * Base Award - XP gained for each individual kill: 100 in Team Deathmatch and Sabotage, 500 in Search and Destroy, 200 in Cage Match (third person) and 50 in other modes.


 * Payback! - Kill an enemy who has killed the player previously. +50XP
 * Buzzkill! - Kill an enemy who is 1 kill short of acquiring a kill streak reward. +100XP
 * Bulls-eye! - Kill an enemy with a throwing knife. +50XP Becomes 0XP at later levels.
 * Flag Runner! - Picked up the flag in a Capture the Flag match. +50XP
 * Stuck! - Stick a Semtex grenade to an enemy. +50XP
 * Rescuer! - Save a wounded teammate by killing the player attacking them. +50XP
 * Hijacker! - Steal an enemy care package. +50XP Sometimes +100XP, later becomes 0XP
 * First Blood! - Be the first person to get a kill in a match. +100XP
 * Offense! - Kill a defender. +50XP In an objective game, kill an enemy who is near a point/flag they control.
 * Defense! - Kill an attacker while near a point/flag one controls in an objective game. +50XP - Kills with air support will count, so long as the player is near one of these points when the kill is earned.
 * Comeback! - Recover from a streak of deaths. +50-100XP - a function of the number of deaths in the deathstreak.
 * Position Secure! - Take an objective. +150XP
 * Double Kill! - Kill two enemies in quick succession. +50XP
 * Triple Kill! - Kill three enemies in quick succession. +75XP
 * Multi Kill! - Kill four or more enemies in quick succession. +100XP
 * Longshot! - Kill an enemy from a distance. +50XP - Score a kill beyond the minimum damage range of a weapon. Sniper rifles, which have no minimum damage, can also get longshots.
 * Share Package! - A teammate saved the player's Care Package from the enemy! - Multiples of 50XP depending on the number of kills usually required for the reward. (eg. a UAV will give +150 EXP, as it requires 3 kills to acquire normally)
 * One Shot One Kill - Kill an uninjured enemy with one sniper rifle shot. +50 XP
 * Flag Return - Return the flag. +50XP
 * Headshot - Kill an enemy with a bullet to the head. +50XP; +500XP - in Search and Destroy, though the on-screen reward will say +50.
 * Crowd Control - Have a teammate kill an enemy that is shooting at your Riot Shield. - +50 for the assist, additional points rewarded for absorbing bullets with the shield.
 * Afterlife - Kill an enemy while dead. +25XP - (eg. Having Martyrdom equipped as a Deathstreak, killing the player's assailant with a dropped live grenade.)
 * Assisted Suicide - Injure an enemy before that enemy kills himself. +350XP
 * Execution! - Kill someone who is in Last Stand or Final Stand with a headshot. +100XP
 * Avenger - Kill an enemy immediately after they have killed a teammate. +50XP
 * Saboteur! - Plant the bomb. +1000 in S&D, +200 in Sabotage and +100 in Demolition.
 * Ninja Defuse - Defuse a bomb almost immediately after it has been planted (On Search & Destroy, Sabotage or Demolition). +1000XP
 * Hero! - Defuse the bomb. +1000 XP if in Search and Destroy, +100 if in Demolition, +150 if in Sabotage.
 * Heroic! - Get a capture point while in last stand. +200 XP
 * Assists give 200 XP in Search and Destroy and 1/5 of the base kill award on the rest of game modes.
 * Destroying a killstreak reward: +0 for Care Package Little Birds, +50 for UAVs and Counter-UAVs, +100 for Sentry Guns, +200 for Attack Helicopters, +300 for Harriers and Chopper Gunners, +400 for Pave Lows and AC130s.
 * Calling in a killstreak reward: +100 for 3-4 killstreaks (UAVs or Counter-UAVs), +150 for 5 killstreaks(Sentry Guns), +200for 6-7 killstreaks (Harrier Airstrikes or Attack Helicopters), +250 for the Emergency Airdrop, +300 for 9 killstreaks (Pave Lows), +350 for 11 killstreaks (Chopper Gunners or AC130's), +500 for EMP, +100 for Tactical Nuke.

Call of Duty: Black Ops
Black Ops contains a similar experience system to Modern Warfare 2, with medals awarded for exceptional accomplishments, and challenges designed to supplement XP gained from matches. However, one can now earn XP from Contracts, and players also receive a Black Ops-exclusive monetary reward, CoD Points, in the order of 10% of the experience earned in game. 5 Killstreak - 150 XP 6-7 Killstreak - 200 XP 8 Killstreak - 250 XP 9 Killstreak - 300 XP 11 Killstreak - 350 XP
 * Above and Beyond - +200 Capture a point while in Second Chance.
 * Afterlife - +100 Killed an enemy while dead.
 * Anti-Bomber - +100 Killed an enemy that was defusing.
 * Assist - +10-80 (10-90 with Nova Gas) Injure an enemy and your teammate kills him. - Points vary depending on how much the player damages the opponent, similar to the assists in World at War.
 * Assisted Suicide - +100 Injured an enemy that killed themselves.
 * Avenger - +50 Killed an enemy who recently killed a teammate.
 * Backstabber - +50 Knife an enemy player in the back.
 * Bankrupt - +10 Kill an enemy with the Tomahawk in Sticks and Stones
 * Bank Shot - +100 Killed an enemy with a banked Tomahawk. - The Tomahawk must bounce off another surface before striking the enemy.
 * Bomber - +100 Detonated the bomb.
 * Buzz Kill - +100 Stopped an enemy short of a killstreak.
 * Comeback - +100 Recovered from a death streak.
 * Defense - +100 Killed an enemy near the defense point.
 * Double Kill - +50 Killed 2 people in rapid succession.
 * Execution - +50 Kill a downed enemy with a headshot.
 * First Blood - +100 Got the first kill.
 * Flag Capture - +250 Captured the enemy flag.
 * Flag Return - +100 Returned the flag.
 * Flag Runner - +100 Pick up the enemy flag.
 * Hero - +500 Defused the bomb.
 * Hijacker - +50 Stole an enemy crate.
 * Longshot - +50 Killed an enemy from a distance.
 * Medic - +50 Revive a downed teammate that is using Second Chance Pro.
 * Multi Kill - +100 Killed more than 3 enemies in rapid succession.
 * Offense - +100 Killed an enemy near the objective.
 * Off The Air - +100 Took out a Valkyrie.
 * One Shot, One Kill - +50 Kill an enemy with one bullet.
 * Payback - +50 Killed the enemy who killed you.
 * Position Secure - +150 Took an objective.
 * Rescuer - +50 Saved a wounded teammate.
 * Road Rage - +100 Destroyed an RC-XD.
 * Saboteur - +500 Planted the bomb.
 * Scalper - +50 Killed an enemy with a Tomahawk.
 * Share Package - +50 Let a teammate take your Care Package.
 * Skewer - Shot and killed an enemy with the Ballistic Knife.
 * Scrapped - Brought down a Helicopter, Spy Plane, or Counter-Spy Plane. (+150 for Spy Plane and Counter-Spy Plane, +400 for Care Package or Attack Helicopter, +500 for Chopper Gunner)
 * Scrapped Assist - +50 Assisted in taking down air support.
 * Stuck - +100 Stick an enemy with an explosive.
 * Triple Kill - +75 Killed 3 people in rapid succession.
 * Turret Kill - +100 Took out an enemy turret.
 * Calling in Killstreaks - 3-4 Killstreak - 100 XP

Call of Duty: Modern Warfare 3
Experience Points return in Modern Warfare 3. The system is similar to the one in Modern Warfare 2, with only differences being more point bonuses, as well as having the ability to buy two hours of doubled XP through Prestige Shop.

Rank Up Your Game
Double XP was also available through the Rank Up Your Game promotion, which ended on December 31, 2011. The promotion allowed players to enter codes found on specially marked Mountain Dew or Doritos products. These codes would give the player 15, 45, or 90 minutes of double XP for Modern Warfare 3, depending on the product. A maximum of 24 hours of Double XP was available for a single gamer ID. The promotion was only available for the Xbox 360 and PS3.

Video
thumb|left|300px|Rank-Up differences on different consoles.