Cooldown reduction

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 you will have a 16% cooldown reduction. Cooldown reduction cannot be increased beyond 40% by absolutely any means.

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 that of or item passive effects with cooldowns such as that of . Most sources of cooldown reduction also does not apply on summoner spells unless specifically stated, e.g. the unique enchantment effect of for boots or the unique passive, Aid, of.

Champion abilities

 * increases cooldown reduction by.
 * increases cooldown reduction by.
 * increases cooldown reduction by.
 * increases cooldown reduction by 10%.
 * increases cooldown reduction by

Masteries

 * increases cooldown reduction by.
 * increases cooldown reduction by.

Runes

 * and runes increase cooldown reduction.

Neutral buffs

 * The buff increases cooldown reduction by 20%

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

 * base cooldown is reduced to 0.5 seconds if the target is poisoned.
 * base cooldown is reduced by 1 second for every stack of on the target.
 * base cooldown is reduced by 1 second if it hits a target. (Stacks up to 2 times)

Flat reduction

 * cooldown is reduced by 2 seconds each time a nearby enemy unit dies.
 * cooldown is reduced by 0.5 seconds each time Amumu is hit by an attack.
 * reduces all of Ezreal's cooldowns by 1 second if it strikes an enemy unit.
 * cooldown is reduced by 1 second for every autoattack.
 * reduces all her abilities' cooldowns by 15 seconds whenever she gets a kill or an assist.
 * innate cooldown is reduced by 1 second for every autoattack.
 * cooldown is reduced by 4.5 seconds if he manages to pick up his axe after using the ability.
 * allows him to reduce all of his other abilities' cooldowns by 1 when he uses an ability.
 * cooldown is reduced by 1 second every time Shen autoattacks, or by 2 seconds every time Shen autoattack while 's shield is up.
 * cooldown is reduced by 0.5 seconds for every autoattack.
 * 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.
 * cooldown is reduced by 1 for every autoattack and 3 seconds with every autoattack on a champion.
 * cooldown is reduced by 2 seconds for every critical strike.
 * reduces his other abilities' cooldowns by 1 second for each strike.
 * innate cooldown is reduced by 4 seconds whenever he uses an ability.
 * on activation, reduces all of Zilean's other cooldowns by 10 seconds.

Cooldown refreshing

 * cooldown is refreshed if the target is afflicted with a moonlight debuff.
 * cooldown is refreshed if Draven catches.
 * cooldown is refreshed if Evelynn gets a kill or an assist on a champion.
 * cooldown is refreshed whenever Fiora gets a kill on a champion, but only halved when she get an assist.
 * cooldown is refreshed if it kills a unit.
 * cooldown is refreshed if Kha'Zix gets a kill or assist on a champion.
 * refreshes all his abilities' cooldowns if he kills an enemy champion under its effect, but halves his cooldowns if he gets an assist instead.
 * cooldown is refreshed whenever Tristana gets a kill or an assist.