Cooldown Reduction (abbreviated as CDR) is a champion statistic that reduces the cooldown of champion 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, 
buffs, and runes. CDR stacks additively and is capped at 40%, which can be increased to 45% with the 
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:
- Static cooldowns.
- Item active abilities (e.g.
Locket of the Iron Solari).
- Item passive effects with cooldowns (e.g.
Guardian Angel).
- Runes.
- Summoner spells.
Gold Value
Although not a basic item, 
Kindlegem is the item from which the cooldown reduction gold value of 
26.6 per % cooldown reduction is derived.
Increasing cooldown reduction
Items
- Archangel's Staff: Passive: Unique – Haste: Grants an additional 10% cooldown reduction.
- Hextech GLP-800: Passive: Unique – Haste: Grants an additional 10% cooldown reduction.
- Lost Chapter: Passive: Unique – Haste: Grants an additional 10% cooldown reduction.
- Luden's Echo: Passive: Unique – Haste: Grants an additional 10% cooldown reduction.
- Seraph's Embrace: Passive: Unique – Haste: Grants an additional 10% cooldown reduction.
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
- Annie's Disintegrate
- Darius' Crippling Strike
- Hecarim's Rampage
- Illaoi's Leap of Faith
- Kindred's Dance of Arrows
Flat reduction
- Aatrox's Deathbringer Stance
- Amumu's Tantrum
- Ezreal's Mystic Shot
- Gragas' Body Slam
- Graves' Quickdraw
- Karma's Gathering Fire
- Katarina's Voracity
- Lucian's Relentless Pursuit
- Master Yi's Alpha Strike
- Miss Fortune's Guns Blazing
- Nocturne's Umbra Blades
- Olaf's Undertow and Reckless Swing
- Shaco's Deceive
- Shyvana's Twin Bite
- Skarner's Crystal Slash
- Syndra's Force of Will
- Taric's Bravado
- Thresh's Death Sentence
- Tryndamere's Spinning Slash
- Xin Zhao's Three Talon Strike
- Zed's Living Shadow
- Ziggs' Short Fuse
- Zilean's Rewind
Percentage reduction
- Evelynn's Hate Spike
- Gnar's Boomerang Throw and Boulder Toss
- Kha'Zix's Evolved Reaper Claws
- Lux's Final Spark
- Master Yi's Highlander
- Nasus' Fury of the Sands
- Nidalee's Pounce
- Sona's Crescendo
- Veigar's Dark Matter
- Yasuo's Steel Tempest
Cooldown refreshing
- Diana's Lunar Rush
- Darius' Noxian Guillotine (rank 3)
- Draven's Blood Rush
- Evelynn's Whiplash
- Irelia's Bladesurge
- Kalista's Rend
- Kha'Zix's Evolved Wings
- Ryze's Overload
- Tristana's Rocket Jump
- Twitch's Ambush
Other cooldown reducing effects
Active ability items
- Cosmic Insight
- Ingenious Hunter
- Perfect Timing ( Guardian Angel, Gargoyle Stoneplate, Wooglet's Witchcap, Wooglet's Witchcrown, Zhonya's Hourglass and Zhonya's Paradox)
| Active Item CDR |  Perfect Timing
| |
|---|---|---|
(     )
| ||
| None | 15% | |
 | 5% | 19.25% |
 0 | 15% | 27.75% |
| 0 / 1 | 20% | 32% |
| 1 / 2 | 25% | 36.25% |
| 2 / 3 | 30% | 40.5% |
| 3 / 4 | 35% | 44.75% |
| 4 / 5 | 40% | 49% |
| 5 | 45% | 53.25% |
- Notes
- Cosmic Insight and Ingenious Hunter stack additively with each other while 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 ▶ | 360s (  )
| 300s (  )
| 240s (   )
| 210s (   )
| 180s (    )
| 90s (  )
| 80s (  )
|
▼  Cooldown reduction
| |||||||
| 5% ()
| 342s | 285s | 228s | 199.5s | 171s | 85.5s | N/A |
10% ( )
| 324s | 270s | 216s | 189s | 162s | 81s | N/A |
| 15% ()
| 306s | 255s | 204s | 178.5s | 153s | 76.5s | N/A |
40% ( )
| N/A | 180s | 144s | 126s | 108s | N/A | 48s |
| 43% ()
| N/A | 171s | 136.8s | 119.7s | 102.6s | N/A | 45.6s |
| 50% ()
| N/A | 150s | 120s | 105s | 90s | N/A | 40s |
| 52.5% ()
| N/A | 142.5s | 114s | 99.75s | 85.5s | N/A | 38s |
Trivia
Last updated: June 1, 2018 – V8.11
One cost and efficient way to reach maximum CDR (45%) is:
- Having both Cosmic Insight and Transcendence, and reaching level 10, giving you 15% CDR.
- Then by buying the Ionian Boots of Lucidity which will provide 10% CDR.
- And finally by purchasing a 20% CDR–item.
- Frozen Heart – 2700
- Iceborn Gauntlet – 2700
- Hextech GLP-800 – 2800
- Nashor's Tooth – 3000
- The Black Cleaver – 3000
- Essence Reaver – 3200
- Archangel's Staff – 3200
- Luden's Echo – 3200
- Trinity Force – 3733
-
The most cooldown reduction any champion can obtain at level 1 with 500 is 20%. To achieve this you must :
- Have the Cosmic Insight rune which will provide 5% CDR.
- Buy Ancient Coin (5% CDR)
- Have the Crest of Insight from the Blue Sentinel (10% CDR)
- Relevant mathematics:
- 5% + 5% + 10% = 20%
| Offensive |  Ability power ·  Attack damage ·  Attack speed ·  Critical strike chance ·  Critical strike damage ·  Armor penetration ·  Magic penetration ·  Life steal ·  Spell vamp ·  True damage
|
|---|---|
| Defensive |   Heal and shield power ·  Health ·  Health regeneration ·  Armor ·  Magic resistance ·  Tenacity ·  Slow resist
|
| Utility | Cooldown reduction ·  Energy ·  Energy regeneration ·  Mana ·  Mana regeneration
|
| Other |  Experience ·  Gold generation ·  Movement speed ·  Range
|
Start a Discussion Discussions about Cooldown reduction
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Does CDR stack or go off of base?
3 messages-
Because it's additional, it will take 25% of the base cooldown. -
Cooldown reduction is based on the ''collective percent'', '''not''' a percent of a redu...
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Is it just me, or did the price of Cooldown Reduction just go down?
3 messages-
CDR has never been at a static price per %. The thing about CDR is that it's priced differently for different roles. Very few APs are go...
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Nothing's changed at all. There's only four items in the game that provide CDR and don't have any other non-measurable factors...
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