Call of Duty: Modern Warfare features a three tiered perk system in both Multiplayer and Spec Ops. Perks are skills that give players a small advantage while on the battlefield. All Perks are separated into three tiers. One Perk per tier must be selected to complete a load out.
Once a player reaches Rank 29, Specialist Mode will become available. Specialist Mode allows six perks to be selected in a loadout; however, killstreaks will be disabled. An extra Perk will be earned after every two kills. The Specialist Bonus becomes available after eight kills, which grants the most Perks and Weapon Perks in the game.
| Perk | Tier | Unlocked | Description |
|---|---|---|---|
| Double Time | Tier 1 | Lv 1 | Doubles the duration of tactical sprint. Increase crouch movement speed by 30%. |
| E.O.D. | Tier 1 | Lv 1 | Take reduced damage from non-killstreak explosives and fire. Additionally, reset the fuse When picking up enemy frag grenades. |
| Scavenger | Tier 1 | Lv 18 | Refills ammo from scavenger packs dropped by dead players. Scavenger packs can also provide throwing knives, but no other lethals. |
| Cold-Blooded | Tier 1 | Lv 29 | Undetectable by AI targeting system and thermal optics. Does not trigger a warning for players using the High Alert Perk. While players will still be visible on player controlled killstreaks and field upgrades, they cannot be marked. |
| Kill Chain | Tier 1 | Lv 34 | Killstreak kills count towards your next killstreaks. Only applies to kill streaks earned this life. Not effective when Specialist Mode is active. Cannot kill chain with killstreaks from another player’s care package. Kill Chain kills don’t help earn nukes. |
| Quick Fix | Tier 1 | Lv 42 | Killing players immediately starts health regeneration. Capturing and holding objectives increases your health regeneration rate. Health regeneration delay is skipped on gun, melee, and throwing knife kills. Health regeneration rate is doubled while carrying, capturing, or holding an objective. |
| Restock | Tier 2 | Lv 1 | Recharge equipment over 30 seconds. Throwing knives can recharge one extra knife. Deploy Grenades and Stim recharge twice as fast. |
| Hardline | Tier 2 | Lv 1 | Killstreaks cost one less kill. Reduces specialist perk cost by one. |
| Overkill | Tier 2 | Lv 8 | Carry two primary weapons. Cannot equip two of the same weapon. Secondaries cannot be equipped. |
| High Alert | Tier 2 | Lv 11 | Edges of the screen pulse yellow when enemies outside your view see you. Triggered by enemies controlling chopper gunners, wheelsons, IAVs, APCs. Does not trigger when enemies have the Alert Perk. |
| Ghost | Tier 2 | Lv 24 | Undetectable by UAVs, Radar Drones, and Heartbeat Sensors. Still appear on Killstreak radar when firing a weapon. Detectable by Advanced UAV, but removes direction. |
| Pointman | Tier 2 | Lv 49 | Killstreaks are earned through game score instead of number of kills. When the Specialist Mode is active, you will earn Perks instead of Killstreaks. |
| Tune Up | Tier 3 | Lv 1 | Reduces the charge time of field upgrades by 40%. |
| Amped | Tier 3 | Lv 1 | Faster weapon swap and rocket launcher reload speed. Does not affect swapping to pistols and knives. Most equipment is used faster. |
| Shrapnel | Tier 3 | Lv 13 | Spawn with an extra piece of lethal equipment. Explosive damage delays enemy health regeneration by 3 seconds. |
| Battle Hardened | Tier 3 | Lv 26 | Reduces the strength of enemy Flash, Stun, EMP, and Gas effects. Immune to Snapshot Grenades. |
| Spotter | Tier 3 | Lv 38 | Detect enemy equipment, Field Upgrades, and Killstreaks through walls. Mark them for your team by aiming down your weapon sights – Advanced UAVs cannot be marked. Hack enemy equipment and Field Upgrades by interacting with them directly. |
| Tracker | Tier 3 | Lv 51 | Enemies leave behind a footprint trail highlighted in red that last approximately 7 seconds. See markers at enemy death locations and hide the death markers of enemies you kill. |