Heart Rate Zone Calculator
Free calculator·Instant results
Max HR
184 bpm (208 − 0.7 × age)
- Heart-rate reserve
- 124 bpm
- Zone 2
- 134–147 bpm
| Zone | % of HR reserve | BPM | Use |
|---|---|---|---|
| Zone 1 | 50–60% | 122–134 | recovery |
| Zone 2 | 60–70% | 134–147 | aerobic base |
| Zone 3 | 70–80% | 147–159 | tempo |
| Zone 4 | 80–90% | 159–172 | threshold |
| Zone 5 | 90–100% | 172–184 | VO2max |
The numbers
How it works
This heart rate zone calculator uses the Karvonen formula, which works from heart-rate reserve (max minus resting) rather than max alone. For the example — age 35, resting 60 bpm, max 184 bpm — the reserve is 124 beats.
That puts Zone 2, the aerobic-base zone most training should sit in, at 134–147 bpm and threshold Zone 4 at 159–172 bpm; Zone 5 starts at 172. A measured max always beats the 208 − 0.7 × age estimate.
Questions
FAQ
What is the Karvonen formula?
Target HR = resting + % × (max − resting). With 60 resting and 184 max, 60% gives the bottom of Zone 2.
What heart rate is Zone 2?
60–70% of heart-rate reserve: 134–147 bpm for the example.
How do I find my max heart rate?
A hard hill repeat session or the end of a 5K race gets close; formulas are a starting point only.
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