Cooldown reduction

For the successor stat, see ability haste.

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Cooldown Reduction (abbreviated as CDR) is a champion statistic that either reduces the cooldown of champion abilities, or the amount of time before an ability can be used again after activation, by a percentage. This stat is tracked and can be seen in the champion stats tooltip. This cooldown reduction is different than the cooldown reduction for summoner spells and items, with the value not being visibly tracked in game. Items and runes may reduce the cooldown for summoner spells and other items.

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. Its formula is: Base Cooldown × (1 − CDR ÷ 100).

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

Based on the type of cooldown reduction, it can affect:

Champion ability cooldowns. (e.g. Lucian's Piercing Light)
Item active effects. (e.g. Locket of the Iron Solari).
Item passive effects with cooldowns. (e.g. Guardian Angel).
Summoner spells. (e.g. Flash)

Cooldown reduction does not apply to the following:

Static cooldowns. (e.g. Anivia's Rebirth)
On-target Cooldowns. (e.g. Jarvan IV's Martial Cadence)
Interrupted Durations. (e.g. Garen's Perseverance)
Rune cooldowns.

Gold Value

Cooldown reduction has a gold value of 26.67 per point.

Increasing cooldown reduction

Items

Unnamed Cooldown Reduction

Various items granted cooldown reduction.

Named Cooldown Reduction

Unique – Haste: Grants an additional 10% cooldown reduction.

Runes

Neutral Buffs

Champion Abilities

Some champions have abilities that decrease their cooldowns by a flat amount, or by a percentage, affecting either their base cooldown or current cooldown, or some abilities can completely 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 Refresh

Other Cooldown Reduction

Ultimate ability

Ultimate ability haste
	None	0	1	2	3	4	5
None	0	6	11	16	21	26	31
1	12	18	23	28	33	38	43
2	24	30	35	40	45	50	55
3	36	42	47	52	57	62	67
4	48	54	59	64	69	74	79

Notes

Ultimate Hunter and Cloudbringer's Grace stack additively with each other while normal CDR stacks multiplicatively with them.

Item Effects

Active Item CDR
	None	0	1	2	3	4	5
None	0%	15%	20%	25%	30%	35%	40%
	5%	20%	25%	30%	35%	40%	45%

Notes

Cosmic Insight and Ingenious Hunter stack additively with each other.
Multiple copies of the same active ability item, and unique named active 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 haste
Base cooldown ▶	420s ()	300s ()	240s ()	210s ()	180s ()	90s ()	80s ()	20s ()
▼ Haste	420s ()	300s ()	240s ()	210s ()	180s ()	90s ()	80s ()	20s ()
12 ()	375s	267.86s	214.29s	187.5s	160.71s	80.36s	N/A	17.86s
18 ()	355.93s	254.24s	203.39s	177.97s	152.54s	76.27s	N/A	16.95s
30 ( )	323.08s	230.77s	184.62s	161.54s	138.46s	69.23s	N/A	15.38s
70 ()	N/A	176.47s	141.18s	123.53s	105.88s	N/A	47.06s	11.76s
82 ()	N/A	164.84s	131.87s	115.38s	98.9s	N/A	43.96s	10.99s
88 ()	N/A	159.57s	127.66s	111.7s	95.74s	N/A	42.55s	10.64s
100 ()	N/A	150s	120s	105s	90s	N/A	40s	10s

Runes

Only 1 rune in the entire game has a way to reduce its cooldown. That rune being Arcane Comet, which gets it's cooldown reduced by a percentage whenever the user deals ability damage to an enemy champion and Arcane Comet is on cooldown.

Trivia

Last updated: December 15th, 2019 – V9.24

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

Having both Cosmic Insight and Transcendence, and reaching level 10, giving 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
- Black Cleaver – 3000
- Archangel's Staff – 3200
- Luden's Echo – 3200
- Essence Reaver – 3300
- Trinity Force – 3773

The most cooldown reduction any champion can obtain at level 1 with 500 is 15%. To achieve this a champion must:

Have the Cosmic Insight rune which will provide 5% CDR.
Have the Crest of Insight from the Blue Sentinel (10% CDR)

Relevant mathematics:

5% + 10% = 15%

Champion statistics

Offensive	Ability power · Attack damage · Attack speed · Critical strike chance · Critical strike damage · Armor penetration · Magic penetration · Life steal · Omnivamp · Physical vamp · True damage
Defensive	Heal and shield power · Health · Health regeneration · Armor · Magic resistance · Tenacity · Slow resist
Utility	Ability haste · Energy · Energy regeneration · Mana · Mana regeneration
Other	Experience · Gold generation · Movement speed · Range

Cooldown reduction

Contents

Increasing cooldown reduction

Items

Unnamed Cooldown Reduction

Named Cooldown Reduction

Runes

Neutral Buffs

Champion Abilities

Base Reduction

Flat Reduction

Percentage Reduction

Cooldown Refresh

Other Cooldown Reduction

Ultimate ability

Item Effects

Summoner spells

Runes

Trivia

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