League of Legends Cooldown Calculator
Calculate final cooldown using Ability Haste (modern LoL) and see its old CDR equivalent.
Legacy CDR % to Ability Haste Converter
Useful for older guides that still mention "40% CDR", "45% CDR", etc.
What this LoL CDR calculator does
If you searched for a LoL CDR calculator, you probably want one thing: your real cooldown after items, runes, and buffs. This tool gives you that instantly and also shows the equivalent cooldown reduction percentage for players who still think in the old CDR system.
Just enter your ability's base cooldown and your total haste. If you're calculating an ultimate, you can also include Ultimate Haste. The calculator then returns:
- Final cooldown in seconds
- Equivalent CDR percentage
- Time saved per cast
- Approximate casts per minute
CDR vs Ability Haste: the important difference
Old system (Cooldown Reduction)
Old League used CDR %, which was capped for most champions and scaled non-linearly in practical build planning. You would usually aim for breakpoints like 30%, 40%, and (in some patches) 45%.
Current system (Ability Haste)
Modern League uses Ability Haste. Instead of directly reducing cooldown by a percentage, haste increases how often you can cast over time.
- Final Cooldown = Base Cooldown / (1 + Haste/100)
- Equivalent CDR % = Haste / (100 + Haste) × 100
This design makes stacking haste feel smoother and avoids hard cap behavior from older seasons.
Quick reference table
| Ability Haste | Equivalent CDR | Multiplier on Cooldown |
|---|---|---|
| 20 | 16.67% | 0.8333x |
| 40 | 28.57% | 0.7143x |
| 60 | 37.50% | 0.6250x |
| 80 | 44.44% | 0.5556x |
| 100 | 50.00% | 0.5000x |
| 120 | 54.55% | 0.4545x |
| 150 | 60.00% | 0.4000x |
| 200 | 66.67% | 0.3333x |
How to use this calculator in game planning
1) Identify your target spell
Pick the ability that matters most to your next fight pattern: poke spell, engage tool, mobility cooldown, or ultimate.
2) Enter realistic haste totals
Add up haste from completed items, runes, and temporary buffs. For ultimates, toggle the checkbox and include Ultimate Haste.
3) Compare build paths
Try multiple totals (for example 40, 70, 100 haste) and see how much real time you save per cast. This is often more useful than guessing from item tooltips.
Practical champion examples
Mages
Mid lane mages often gain value from reaching repeated spell rotation windows. A 10-second cooldown at 80 haste becomes about 5.56 seconds, which can completely change wave control and skirmish pacing.
Supports
Enchanters and engage supports can use cooldown math for shields, peels, and initiation windows. Knowing your exact timer can decide whether you re-engage or disengage after the first trade.
Ultimate-reliant champions
If your champion depends on ultimate uptime, include Ultimate Haste separately. This helps when comparing runes or items that specifically buff ultimate cooldowns instead of all abilities.
FAQ
Is CDR still in League of Legends?
No. The in-game stat is Ability Haste, but many players still search for "CDR calculator," which is why this page shows both formats.
Can I get infinite cooldown reduction?
No. Cooldowns get lower as haste increases, but never reach zero. You get diminishing percentage returns, though each haste point still increases cast frequency in a consistent way.
Why show equivalent CDR if it is outdated?
It helps translate older build guides and videos. For example, the old 40% CDR benchmark corresponds to about 66.67 Ability Haste.
Final thoughts
A good LoL cooldown calculator should be fast, accurate, and practical. Use this one to test spell breakpoints before you queue up, compare item choices, and optimize your champion's real combat uptime.