Heart rate zone calculator
Training zones turn a heart rate monitor into something useful. This estimates your maximum, then sets the five zones either as percentages of it or, better, of your heart rate reserve.
- Where that came from
- Estimated from age
- Heart rate reserve
- 124
- Aerobic zone
- 146 – 159
- Easy endurance zone
- 134 – 146
- Threshold zone
- 159 – 171
- Tanaka estimate
- 184
- The old 220 − age estimate
- 185
| Zone | Beats per minute | Intensity |
|---|---|---|
| zone:z1 | 122 – 134 | 50–60 % |
| zone:z2 | 134 – 146 | 60–70 % |
| zone:z3 | 146 – 159 | 70–80 % |
| zone:z4 | 159 – 171 | 80–90 % |
| zone:z5 | 171 – 184 | 90–100 % |
Estimates for healthy adults. Beta blockers and some other medications change heart rate substantially, and chest pain or unusual breathlessness during exercise is a reason to see a doctor rather than adjust a zone.
The formula
Maximum heart rate is estimated by Tanaka: 208 − 0.7 × age. The Karvonen method sets each zone at resting + (maximum − resting) × percentage; the simpler method uses maximum × percentage.
Worked example
At 35 with a resting rate of 60, the estimated maximum is 184 and the reserve 124. The aerobic zone by Karvonen is then 146 to 159 beats per minute.
How to use it
- 1Measure your resting rate first thing in the morning, before getting up, across several days.
- 2Enter a measured maximum if you have one from a lab or a hard field test — it beats any age formula.
- 3Prefer the reserve method. It accounts for your fitness, which the percentage-of-maximum method ignores.
Questions people ask
Why not 220 − age?
It is simple and systematically wrong, overestimating for younger adults and underestimating past 40, with a standard deviation of around 10 to 12 beats. Tanaka fits the data better. Both are shown so you can see the gap.
Is the fat-burning zone real?
Easy effort does burn a higher proportion of fat, but harder effort burns more total energy. For body composition, total energy and consistency matter more than the zone you train in.
Last reviewed: 2026-10-20