Cooldown Reduction (CDR & Ability Haste)
Calculate the effective cooldown of an ability from cooldown reduction or ability haste and how many casts you get per minute, free online.
About this calculator
With cooldown reduction (CDR) the cooldown becomes base × (1 − CDR). With ability haste (League of Legends style) it is base × 100 ÷ (100 + haste), so each point of haste gives diminishing returns. The effective increase in casts equals the base cooldown ÷ the new cooldown.