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 buff 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


Item Cost Amount Availability
Abyssal Mask item Abyssal Mask2900 Gold10 %Common
Adaptive Helm item Adaptive Helm2800 Gold10 %Common
Ancient Coin item Ancient Coin350 Gold5 %Summoner's Rift
Ardent Censer item Ardent Censer2300 Gold10 %Common
Athene's Unholy Grail item Athene's Unholy Grail2100 Gold10 %Common
Banner of Command item Banner of Command2200 Gold10 %Common
Banshee's Veil item Banshee's Veil3000 Gold10 %Common
Caulfield's Warhammer item Caulfield's Warhammer1100 Gold10 % (Unique)Common
Death's Dance item Death's Dance3500 Gold10 %Common
Duskblade of Draktharr item Duskblade of Draktharr2900 Gold10 %Common
Essence Reaver item Essence Reaver3400 Gold10 % (Unique)Common
Eye of Ascension item Eye of Ascension0 Gold10 %Summoner's Rift
Eye of Frost item Eye of Frost0 Gold10 %Summoner's Rift
Eye of the Aspect item Eye of the Aspect0 Gold10 %Summoner's Rift
Eye of the Watchers item Eye of the Watchers0 Gold10 %Summoner's Rift
Fiendish Codex item Fiendish Codex900 Gold10 % (Unique)Common
Forbidden Idol item Forbidden Idol800 Gold10 % (Unique)Common
Frostfang item Frostfang850 Gold10 %Summoner's Rift
Frozen Heart item Frozen Heart2700 Gold20 %Common
Glacial Shroud item Glacial Shroud900 Gold10 % (Unique)Common
Hextech Protobelt-01 item Hextech Protobelt-012500 Gold10 %Common
Iceborn Gauntlet item Iceborn Gauntlet2700 Gold20 %Common
Infernal Mask item Infernal Mask3900 Gold10 %Common
Ionian Boots of Lucidity item Ionian Boots of Lucidity900 Gold10 % (Unique)Common
Kindlegem item Kindlegem800 Gold10 % (Unique)Common
Knight's Vow item Knight's Vow2200 Gold10 %Common
Lich Bane item Lich Bane3200 Gold10 %Common
Lord Van Damm's Pillager item Lord Van Damm's Pillager3000 Gold10 %Twisted Treeline
Maw of Malmortius item Maw of Malmortius3250 Gold10 %Common
Mikael's Crucible item Mikael's Crucible2100 Gold10 %Summoner's Rift, Howling Abyss
Morellonomicon item Morellonomicon2900 Gold20 % (Unique)Common
Nashor's Tooth item Nashor's Tooth3000 Gold20 % (Unique)Common
Nomad's Eye item Nomad's Eye0 Gold10 %Summoner's Rift
Nomad's Medallion item Nomad's Medallion850 Gold10 %Summoner's Rift
Ohmwrecker item Ohmwrecker2650 Gold10 %Summoner's Rift
Redemption item Redemption2100 Gold10 %Summoner's Rift, Howling Abyss
Remnant of the Ascended item Remnant of the Ascended1500 Gold10 %Summoner's Rift
Remnant of the Aspect item Remnant of the Aspect1900 Gold10 %Summoner's Rift
Remnant of the Watchers item Remnant of the Watchers1800 Gold10 %Summoner's Rift
Righteous Glory item Righteous Glory2650 Gold10 %Common
Salvation item Salvation2600 Gold10 %Summoner's Rift, Howling Abyss
Sheen item Sheen1050 Gold10 %Common
Spirit Visage item Spirit Visage2800 Gold10 %Common
Stinger item Stinger1100 Gold10 % (Unique)Common
The Black Cleaver item The Black Cleaver3000 Gold20 %Common
The Obsidian Cleaver item The Obsidian Cleaver4000 Gold20 %Common
Ancient Coin item Timeworn Ancient Coin350 Gold5 %Twisted Treeline
Face of the Mountain item Timeworn Face of the Mountain2200 Gold10 %Twisted Treeline
Frostfang item Timeworn Frostfang850 Gold10 %Twisted Treeline
Frost Queen's Claim item Timeworn Frost Queen's Claim2200 Gold10 %Twisted Treeline
Nomad's Medallion item Timeworn Nomad's Medallion850 Gold10 %Twisted Treeline
Talisman of Ascension item Timeworn Talisman of Ascension2200 Gold10 %Twisted Treeline
Trinity Force item Trinity Force3733 Gold20 %Common
Trinity Fusion item Trinity Fusion4733 Gold20 %Common
Warmog's Armor item Warmog's Armor2850 Gold10 % (Unique)Common
Warrior item Warrior2625 Gold10 %Classic
Youmuu's Ghostblade item Youmuu's Ghostblade2900 Gold10 %Common
Zeke's Convergence item Zeke's Convergence2250 Gold10 %Common
Zhonya's Hourglass item Zhonya's Hourglass2900 Gold10 %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.


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%
Ingenious Hunter rune1 16% 28.6%
Ingenious Hunter rune1Cosmic Insight rune 21% 32.85%
Ingenious Hunter rune2 22% 33.7%
Ingenious Hunter rune2Cosmic Insight rune 27% 41.6%
Ingenious Hunter rune3 28% 38.8%
Ingenious Hunter rune3Cosmic Insight rune 33% 43.05%
Ingenious Hunter rune4 34% 43.9%
Ingenious Hunter rune4Cosmic Insight rune 39% 48.15%
Ingenious Hunter rune5 40% 49%
Ingenious Hunter rune5Cosmic Insight rune 45% 53.25%
  • Cosmic Insight rune Cosmic Insight and Ingenious Hunter rune Ingenious Hunter stack additively with each other while Perfect Timing rune Perfect Timing stacks multiplicatively with them.
  • 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
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) / (Unsealed Spellbook rune) 255s 204s 178.5s 153s 63.25s N/A
20% (Unsealed Spellbook runeCosmic Insight rune) 240s 192s 168s 144s 60s N/A
25% (Unsealed Spellbook runeIonian Boots of Lucidity item) 225s 180s 157.5s 135s 56.25s N/A
30% (Unsealed Spellbook runeIonian Boots of Lucidity itemCosmic Insight rune) 210s 168s 147s 126s 52.5s 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
49% (Howling Abyss iconUnsealed Spellbook rune) 153s 122.4s 107.1s 91.8s N/A 40.8s
50% (Howling Abyss iconIonian Boots of Lucidity item) 150s 120s 105s 90s N/A 40s
52% (Howling Abyss iconUnsealed Spellbook runeCosmic Insight rune) 144s 115.2s 100.8s 86.4s N/A 38.4s
52.5% (Howling Abyss iconIonian Boots of Lucidity itemCosmic Insight rune) 142.5s 114s 99.75s 85.5s N/A 38s
57.5% (Howling Abyss iconUnsealed Spellbook runeIonian Boots of Lucidity item) 127.5s 102s 89.25s 76.5s N/A 34s
60% (Howling Abyss iconUnsealed Spellbook runeIonian Boots of Lucidity itemCosmic Insight rune) 120s 96s 84s 72s N/A 32s


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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