Differences Between Ability Haste and Cooldown Reduction
The League of Legends introduced Ability Haste (AH) in pre-season 11, replacing cooldown reduction (CDR). One major difference is that CDR uses percentages, while AH uses numbers.
CDR had a maximum cap of 40%, as higher percentages made it too powerful. In contrast, AH has no specific limit, but it can’t be abused. Players can build up AH to significantly reduce cooldowns, but not to an extreme extent.
Another difference is how they affect cooldowns. CDR provides a huge decrease in cooldowns, while AH decreases cooldowns based on the number of points obtained. For example, getting 10 points of AH reduces cooldowns by approximately 10%. AH brings the same impact on cooldowns, while CDR’s impact increases with higher percentages.
How Much Ability Haste Can You Have?
There is no limit to the amount of AH you can have in a match as long as it comes from items. The table below shows the conversion between AH and CDR percentages to give a better understanding of their differences:
| Ability Haste | Cooldown Reduction |
| 5.26 | 5 % |
| 11.11 | 10 % |
| 566.67 | 85 % |
| 900 | 90 % |
| 1900 | 95 % |
The maximum AH percentage is 50%, as reaching higher percentages requires a large amount of AH. Striving for 100 AH is a worthwhile goal, but it requires choosing the right runes and items for your build.
Conclusion
In summary, AH and CDR have significant differences. AH increases linearly with each point obtained, while CDR increases multiplicatively. While there is no limit to AH, it is practically impossible to reach a CDR higher than 50%. Understanding these differences can help players utilize AH effectively in their builds.