Karvonen calculator
Calculate target heart rate using heart rate reserve. More accurate than a plain percentage of HRmax because it accounts for your resting heart rate.
Everything is computed in your browser โ the values you enter are never sent or stored.
Result
- Target HR at 70% HRR
- 146 bpm
- Heart rate reserve (HRR)
- 130 bpm
Intensity ranges
| % HRR | Heart rate | Use |
|---|---|---|
| 30% | 94 bpm | very light |
| 40% | 107 bpm | light |
| 60% | 133 bpm | moderate |
| 80% | 159 bpm | high |
| 90% | 172 bpm | very high |
If you take medication affecting heart rate (e.g. beta blockers), HR zones may be unreliable โ train by perceived exertion instead.
How we calculate this
- HRR = HRmax โ HRrest
- TargetHR = HRrest + intensity ร HRR
The formulas come from the appโs domain specification and are covered by unit tests. The same code powers zones inside the app.
Want these numbers to feed your plan automatically?
In the app, zones update after every test and the plan adapts to your data and how you feel.
This calculator is informational and does not replace a doctor, physiotherapist or coach. Results based on population formulas are estimates, not measurements. Read the full disclaimer โ