Ability haste and cooldowns

After an ability is used it goes on cooldown, a wait before it can be cast again. Ability haste is the stat that shortens it. Every champion starts at zero; it comes from items, runes and some abilities.

The formula

Why every point counts the same

The cooldown shrinks by less with each point you add, but look at the last column: every 25 ability haste adds the same 1.5 casts per minute. Ability haste is linear in what matters, how often you get to use the ability. There is no point at which it starts to give less.

This is why ability haste has no cap. The older stat it replaced, cooldown reduction, was a percentage and had to be capped, because each percent was worth more than the one before and 100% would have meant no cooldowns at all.

What it does not change

• Summoner spells. They have their own summoner spell haste, from a few runes and items. Ability haste does nothing for Flash.
• Item actives. An item's active keeps the cooldown its tooltip lists.

Reading the number

To turn ability haste into a percentage, use 1 − 100 ÷ (100 + haste). 20 ability haste shortens cooldowns by about 17%; 60 by 37.5%. Ultimate haste works the same way but applies to the ultimate only.