Cooldown Reduction (abbreviated as CDR) is a champion statistic that reduces the cooldown of abilities, or the amount of time before an ability can be used again after activation, by a percentage. There are some items that separately reduce the cooldown for summoner spells or item active abilities, but do not grant cooldown reduction.

Cooldown reduction can be granted by items, Crest of Insight.png buffs, and runes. CDR stacks additively and is capped at 40%, which can be increased to 45% with the Cosmic Insight rune Cosmic Insight rune.

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

Cooldown reduction does not apply to:

Although not a basic item, Fiendish Codex item Fiendish Codex is the item from which the cooldown reduction gold value of Gold 24.75 per % cooldown reduction is derived.

Increasing Cooldown Reduction

Items

Item Cost Amount Availability
Abyssal Mask item Abyssal Mask2900 Gold 10 %Common
Adaptive Helm item Adaptive Helm2800 Gold 10 %Common
Ancient Coin item Ancient Coin350 Gold 5 %Classic
Ardent Censer item Ardent Censer2300 Gold 10 %Common
Athene's Unholy Grail item Athene's Unholy Grail2100 Gold 10 %Common
Banner of Command item Banner of Command2200 Gold 10 %Common
Banshee's Veil item Banshee's Veil3000 Gold 10 %Common
Caulfield's Warhammer item Caulfield's Warhammer1100 Gold 10 % (Unique)Common
Death's Dance item Death's Dance3500 Gold 10 %Common
Duskblade of Draktharr item Duskblade of Draktharr2900 Gold 10 %Common
Essence Reaver item Essence Reaver3400 Gold 10 % (Unique)Common
Eye of the Equinox item Eye of the Equinox2300 Gold 10 %Summoner's Rift
Eye of the Oasis item Eye of the Oasis1900 Gold 10 %Summoner's Rift
Eye of the Watchers item Eye of the Watchers2200 Gold 10 %Summoner's Rift
Face of the Mountain item Face of the Mountain2200 Gold 10 %Classic
Fiendish Codex item Fiendish Codex900 Gold 10 % (Unique)Common
Forbidden Idol item Forbidden Idol800 Gold 10 % (Unique)Common
Frost Queen's Claim item Frost Queen's Claim2200 Gold 10 %Classic
Frostfang item Frostfang850 Gold 10 %Classic
Frozen Heart item Frozen Heart2700 Gold 20 %Common
Glacial Shroud item Glacial Shroud900 Gold 10 % (Unique)Common
Hextech Protobelt-01 item Hextech Protobelt-012500 Gold 10 %Common
Iceborn Gauntlet item Iceborn Gauntlet2700 Gold 20 %Common
Infernal Mask item Infernal Mask3900 Gold 10 %Common
Ionian Boots of Lucidity item Ionian Boots of Lucidity900 Gold 10 % (Unique)Common
Kindlegem item Kindlegem800 Gold 10 % (Unique)Common
Knight's Vow item Knight's Vow2200 Gold 10 %Common
Lich Bane item Lich Bane3200 Gold 10 %Common
Lord Van Damm's Pillager item Lord Van Damm's Pillager3000 Gold 10 %Twisted Treeline
Maw of Malmortius item Maw of Malmortius3250 Gold 10 %Common
Mikael's Crucible item Mikael's Crucible2100 Gold 10 %Summoner's Rift, Howling Abyss
Morellonomicon item Morellonomicon2900 Gold 20 % (Unique)Common
Nashor's Tooth item Nashor's Tooth3000 Gold 20 % (Unique)Common
Nomad's Medallion item Nomad's Medallion850 Gold 10 %Classic
Ohmwrecker item Ohmwrecker2650 Gold 10 %Summoner's Rift
Redemption item Redemption2100 Gold 10 %Summoner's Rift, Howling Abyss
Righteous Glory item Righteous Glory2650 Gold 10 %Common
Salvation item Salvation2600 Gold 10 %Summoner's Rift, Howling Abyss
Sheen item Sheen1050 Gold 10 %Common
Spirit Visage item Spirit Visage2800 Gold 10 %Common
Stinger item Stinger1100 Gold 10 % (Unique)Common
Talisman of Ascension item Talisman of Ascension2200 Gold 10 %Classic
The Black Cleaver item The Black Cleaver3000 Gold 20 %Common
The Obsidian Cleaver item The Obsidian Cleaver4000 Gold 20 %Common
Trinity Force item Trinity Force3733 Gold 20 %Common
Trinity Fusion item Trinity Fusion4733 Gold 20 %Common
Warmog's Armor item Warmog's Armor2850 Gold 10 % (Unique)Common
Warrior item Warrior1625 Gold 10 %Classic
Youmuu's Ghostblade item Youmuu's Ghostblade2900 Gold 10 %Common
Zeke's Convergence item Zeke's Convergence2250 Gold 10 %Common
Zhonya's Hourglass item Zhonya's Hourglass2900 Gold 10 %Summoner's Rift, Howling Abyss
  • Essence Reaver item Essence Reaver: Passive: Unique: Gain 0% - 20% (based on critical strike chance) additional cooldown reduction. This bonus does not include the critical strike chance given by this item.

Runes

Champion Abilities

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 circumvent the 40% cooldown reduction cap.

  • Depending on built-in reduction type:
    • Base (applies before CDR)
    • Flat (applies after CDR)
    • Percent (applies to base / current / total cooldown)
    • Refresh (cooldown is immediately reduced to 0)

Base reduction

Flat reduction

Percentage reduction

Cooldown refreshing

Other cooldown reducing effects

Active Ability Items

Active Item CDR Perfect Timing rune Perfect Timing
(Gargoyle Stoneplate itemZhonya's Hourglass itemZhonya's Paradox itemWooglet's Witchcap itemWooglet's Witchcrown item)
None 15%
Cosmic Insight rune 5% 19.25%
Ingenious Hunter rune0 10% 23.5%
Ingenious Hunter rune0Cosmic Insight rune 15% 27.75%
Ruby Sightstone item 20% 32%
Ruby Sightstone itemCosmic Insight rune 25% 36.25%
Ruby Sightstone itemIngenious Hunter rune0 30% 40.5%
Ruby Sightstone itemIngenious Hunter rune0Cosmic Insight rune 35% 44.75%
Ingenious Hunter rune5 40% 49%
Ingenious Hunter rune5Cosmic Insight rune 45% 53.25%
Ingenious Hunter rune5Ruby Sightstone item 60% 66%
Ingenious Hunter rune5Ruby Sightstone itemCosmic Insight rune 65% 70.25%
Notes
  • Multiple copies of the same active ability item share a global cooldown.
    • Purchasing yet another copy while the already owned ones are still on CD will make the newest one's sync up with the others'.

Summoner Spells

Summoner spell CDR
Base cooldown ▶ 300s
(FlashTeleport)
240s
(ClarityHeal)
210s
(CleanseExhaustIgnite)
180s
(BarrierGhost)
75s
(Smite)
80s
(Mark)
Cooldown reduction icon Cooldown reduction
5% (Cosmic Insight rune) 285s 228s 199.5s 171s 71.75s N/A
10% (Ionian Boots of Lucidity item) 270s 216s 189s 162s 67.5s N/A
15% (Ionian Boots of Lucidity itemCosmic Insight rune) 255s 204s 178.5s 153s 63.25s N/A
25% (Unsealed Spellbook rune) 225s 180s 157.5s 135s 56.25s N/A
30% (Unsealed Spellbook runeCosmic Insight rune) 210s 168s 147s 126s 52.5s N/A
35% (Unsealed Spellbook runeIonian Boots of Lucidity item) 195s 156s 136.5s 117s 48.75s N/A
40% (Unsealed Spellbook runeIonian Boots of Lucidity itemCosmic Insight rune) 180s 144s 126s 108s 45s N/A
40% (Howling Abyss icon) 180s 144s 126s 108s N/A 48s
43% (Howling Abyss iconCosmic Insight rune) 171s 136.8s 119.7s 102.6s N/A 45.6s
50% (Howling Abyss iconIonian Boots of Lucidity item) 150s 120s 105s 90s N/A 40s
52.5% (Howling Abyss iconIonian Boots of Lucidity itemCosmic Insight rune) 142.5s 114s 99.75s 85.5s N/A 38s
55% (Howling Abyss iconUnsealed Spellbook rune) 135s 108s 94.5s 81s N/A 36s
58% (Howling Abyss iconUnsealed Spellbook runeCosmic Insight rune) 126s 100.8s 88.2s 75.6s N/A 33.6s
65% (Howling Abyss iconUnsealed Spellbook runeIonian Boots of Lucidity item) 105s 84s 73.5s 63s N/A 28s
68% (Howling Abyss iconUnsealed Spellbook runeIonian Boots of Lucidity itemCosmic Insight rune) 96s 76.8s 67.2s 57.6s N/A 25.6s

Trivia

Last updated: November 21, 2017 – V7.23

One cost and efficient way to reach maximum CDR (45%) is:


The most cooldown reduction any champion can obtain at level 1 with Gold 500 is 20%. To achieve this you must :

Relevant mathematics:
5% + 5% + 10%  = 20%

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