冷却缩减

Cooldown reduction (abbreviated as CDR) is a champion statistic that reduces the cooldown of abilities, or the amount of time you must wait before an ability can be used again once you activated it, by a percentage.

Cooldown reduction is granted by items, buffs, runes and masteries, as well as some passive abilities.

Cooldown reduction works additively. If you have a 6% cooldown reduction from masteries, and a 10% cooldown reduction from Stinger you will have a 16% cooldown reduction. Cooldown reduction cannot be increased beyond 40% by absolutely any means.

Cooldown reduction is unique among the same item. So 2 Nashor's Tooth (+25%) will only grant the bonus of +25%, but a Nashor's Tooth (+25%) and a Fiendish Codex (+10%) will grant a +35% bonus.

Cooldown reduction is determined at the moment an ability is activated. Increasing/decreasing your cooldown reduction while the skill is on cooldown will not affect the cooldown.

Cooldown reduction does not apply on item active abilities such as those of Deathfire Grasp or Guardian Angel.

Increasing cooldown reduction

Items

There are several items which reduce the cooldown of your abilities. Cooldown Reduction granted by an item is always a unique passive.

• Athene's Unholy Grail: +15% cooldown reduction, +90 ability power, +40 magic resist, +15 mana regeneration, UNIQUE: Restores 12% of your max mana on kill or assist, UNIQUE: Increases your mana regeneration by 1% per 1% mana you are missing. 2950 gold.
• Elixir of Brilliance: On use, grants +10% cooldown reduction for 4 minutes, +20-40 ability power based on champion level for 4 minutes. 250 gold.
• Fiendish Codex: 10% cooldown reduction, +30 ability power, +7 mana regeneration per 5 seconds. 1125 gold.
• Frozen Heart: +20% cooldown reduction, +99 armor, +500 mana. Unique passive aura: Reduces the attack speed of nearby enemies by 20%. 2775 gold.
• Glacial Shroud: +15% cooldown reduction, +425 mana, +45 armor. 1525 gold.
• Hextech Sweeper: +10% cooldown reduction, +25 ability power, +300 health. Unique passive: Your spell damage grants vision of your target for 4 seconds. Unique active: Covers an area with stealth-detecting mist for 6 seconds, granting vision of units which pass through it for 10 seconds. 60 second cooldown. (1000 Range, 375 AOE estimate). 1435 gold.
• Ionian Boots of Lucidity: +15% cooldown reduction. Unique passive: Enhanced movement 2. 1050 gold.
• Kindlegem: +10% cooldown reduction, +200 health. 850 gold.
• Lord Van Damm's Pillager: +10% cooldown reduction. +40 Attack Damage, +350 Health. Unique Passive: 10% Spell Vamp. Unique Passive: +25 Armor Penetration. 2962 gold.
• Mejai's Soulstealer: +15% cooldown reduction (at 20 stacks.) +20 ability power. Unique passive: Your champion gains 8 ability power per stack, receiving 2 stacks for a kill or 1 stack for an assist. This effect can stack 20 times; you lose a third of your stacks if you die. 1235 gold.
• Morello's Evil Tome: +20% cooldown reduction, +75 ability power, +12 mana regeneration per 5 seconds. Unique Active: Inflicts target enemy champion with Grievous Wound, causing 50% reduced healing and regeneration for 8 seconds(20 second cooldown). 2330 gold.
• Nashor's Tooth: +25% cooldown reduction, +50% attack speed, +65 ability power, +10 mana regeneration per 5 seconds. 2615 gold.
• Randuin's Omen: +5% cooldown reduction, +350 health, +75 armor, +25 health regeneration per 5 seconds. Unique passive: 20% chance on being hit to slow the attacker's movement and attack speeds by 25% for 3 seconds. Unique active: Slows movement speed and attack speed of all surrounding enemy units by 35% for 1 second + 0.5 seconds for each 100 armor and magic resistance. 60 second cooldown. 3075 gold.
• Shurelya's Reverie: +15% cooldown reduction, +330 health, +30 health regen per 5 seconds, +15 mana regeneration per 5 seconds. Unique active: Nearby champions gain 40% movement speed for 3 seconds (60 second cooldown). 2200 gold.
• Soul Shroud: Unique passive aura: +10% cooldown reduction to nearby allied champions. +520 health. Unique passive aura: Gives nearby allied champions 12 mana regeneration per 5. 2285 gold.
• Spirit Visage: +10% cooldown reduction, +30 magic resistance, +250 health. Unique passive: Increases healing and regeneration on yourself by 15%. 1550 gold.
• Stinger: +10% cooldown reduction, +40% attack speed. 1090 gold.
• The Brutalizer: +10% cooldown reduction, +25 attack damage. Unique passive: +15 armor penetration. 1337 gold.
• Youmuu's Ghostblade: +15% cooldown reduction, +30 attack damage, +15% critical strike chance. Unique passive: +20 armor penetration. Unique active: You gain +20% movement speed and +50% attack speed for 4 seconds. Attacking enemy units with melee attacks increases the duration by 2 to a maximum of 8 seconds. 60 second cooldown. 2687 gold.
• Zeke's Herald: Unique passive: 15% cooldown reduction.+250 health. Unique aura: Nearby allied champions gain +20% attack speed and +12% life steal. 2145 gold.

Champion abilities

• Heimerdinger's UPGRADE!!! increases cooldown reduction by 10% / 15% / 20%.
• Ryze's Overload increases cooldown reduction by 2% / 4% / 6% / 8% / 10%.
• Twisted Fate's Stacked Deck increases cooldown reduction by 3% / 6% / 9% / 12% / 15%.
• Viktor's Augment: Gravity increases cooldown reduction by 10%.
• Zyra's Rampant Growth increases cooldown reduction by 4% / 8% / 12% / 16% / 20%

Masteries

• Sorcery Sorcery increases cooldown reduction by 1% / 2% / 3% / 4%.
• Enlightenment Enlightenment increases cooldown reduction by 0.15% / 0.30% / 0.45% per level (2.7% / 5.4% / 8.1% cooldown reduction at level 18).
• Intelligence Intelligence increases cooldown reduction by 2% / 4% / 6%.

Runes

• Celerity and Focus runes increase cooldown reduction.

Neutral buffs

• The Crest of the Ancient Golem buff increases cooldown reduction by 20%.
• The Crest of Nature's Fury buff increases cooldown reduction by 10%.

Lowering cooldowns

Some champions have abilities that decrease their cooldowns by a flat amount, either their base cooldown or current cooldown, or entirely refresh their cooldown. Base reduction occurs before cooldown reduction takes effect while flat reduction occurs after cooldown reduction takes effect. By using those, a champion can disregard the 40% cooldown reduction cap.

Note: Only the cooldown reduction of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them.

Base reduction

• Cassiopeia's Twin Fang base cooldown is reduced to 0.5 seconds if the target is poisoned.
• Darius' Crippling Strike base cooldown is reduced by 1 second for every stack of Hemorrhage on the target.
• Fiora's Burst of Speed base cooldown is reduce by half whenever she gets an assist.
• Hecarim's Rampage base cooldown is reduced by 1 second if it hits a target. (Stacks up to 2 times)
• Master Yi's Highlander reduces all his abilities' base cooldowns by half whenever he gets an assist while under the effect of the skill.

Flat reduction

• Alistar's Triumphant Roar cooldown is reduced by 2 seconds each time a nearby enemy unit dies.
• Amumu's Tantrum cooldown is reduced by 0.5 seconds each time Amumu is hit by an attack.
• Ezreal's Mystic Shot reduces all of Ezreal's cooldowns by 1 second if it strikes an enemy unit.
• Graves' Quickdraw cooldown is reduced by 1 second for every autoattack.
• Katarina's Voracity reduces all her abilities' cooldowns by 15 seconds whenever she gets a kill or an assist.
• Nocturne's Umbra Blades innate cooldown is reduced by 1 second for every autoattack.
• Olaf's Undertow cooldown is reduced by 4.5 seconds if he manages to pick up his axe after using the ability.
• Ryze's Arcane Mastery allows him to reduce all of his other abilities' cooldowns by 1 when he uses an ability.
• Shen's Ki Strike cooldown is reduced by 1.5 seconds every time Shen autoattacks, or by 3 seconds every time Shen autoattack while Feint's shield is up.
• Shyvana's Twin Bite cooldown is reduced by 0.5 seconds for every autoattack.
• Skarner's Energize allows Skarner to reduces all of his abilities' cooldowns by 1 second for each successful autoattack on an enemy champion and 0.5 seconds for each successful autoattack on a non-champion target.
• Taric's Imbue cooldown is reduced by 1 for every autoattack and 3 seconds with every autoattack on a champion.
• Tryndamere's Spinning Slash cooldown is reduced by 2 seconds for every critical strike.
• Xin Zhao's Three Talon Strike reduces his other abilities' cooldowns by 1 second for each strike.
• Ziggs' Short Fuse innate cooldown is reduced by 4 seconds whenever he uses an ability.
• Zilean's Rewind on activation, reduces all of Zilean's other cooldowns by 10 seconds.

Cooldown refreshing

• Darius' Noxian Guillotine cooldown is refreshed if it kills a champion.
• Diana's Lunar Rush cooldown is refreshed if the target is afflicted with a moonlight debuff.
• Draven's Blood Rush cooldown is refreshed if Draven catches Spinning Axe.
• Evelynn's Dark Frenzy cooldown is refreshed if Evelynn gets a kill or an assist on a champion.
• Fiora's Burst of Speed cooldown is refreshed if Fiora kills a champion.
• Irelia's Bladesurge cooldown is refreshed if it kills a unit.
• Kha'Zix's Evolved Leap Evolved Leap cooldown is refreshed if Kha'Zix gets a kill or assist on a champion.
• Master Yi's Highlander refreshes all Master Yi's cooldowns whenever he kills a champion while under the effect of the skill.
• Tristana's Rocket Jump cooldown is refreshed whenever Tristana gets a kill or an assist.