Heart Rate Zone Calculator
Work out your heart-rate training zones from your maximum heart rate, and what each zone trains.
Training by intensity
Heart-rate zones divide the range up to your maximum into bands, each representing a level of effort that trains your body differently. Training by zone lets you match your effort to your goal — easy recovery, fat-burning endurance, or hard performance work — rather than guessing. This works out your zones from your maximum heart rate.
The five zones
Zones are usually given as percentages of your maximum heart rate, and each has a purpose:
| Zone | % of max HR | Feels like | Trains |
|---|---|---|---|
| 1 | 50–60% | Very easy | Recovery, warm-up |
| 2 | 60–70% | Comfortable, can chat | Endurance, fat use |
| 3 | 70–80% | Moderate, harder to talk | Aerobic fitness |
| 4 | 80–90% | Hard | Speed, performance |
| 5 | 90–100% | Maximal, unsustainable | Peak power, short bursts |
A common insight is that much endurance training should sit in the easier zones 1 and 2, where you build an aerobic base sustainably, with harder zones used sparingly.
Zones are a guide, built on an estimate
Because zones are calculated from maximum heart rate, and that maximum is usually itself an estimate, the zone boundaries are approximate rather than exact — treat them as useful bands, not precise thresholds. They are still a genuinely helpful way to structure training and avoid the common trap of doing every session at a moderate, unfocused effort. This is general information, not medical advice; if you have a heart condition or are new to intense exercise, consult a doctor before training hard, and ease into higher zones gradually.
Frequently asked questions
What are heart-rate zones for?
They match your effort to your goal — easy recovery, endurance, or hard performance — so training is focused rather than a guess at intensity.
Which zone should I train in most?
For endurance, much training should sit in the easier zones 1 and 2 to build an aerobic base, with harder zones used more sparingly.
How accurate are the zones?
Approximate — they are calculated from an estimated maximum heart rate, so treat the boundaries as useful bands rather than precise thresholds.
Is this medical advice?
No — it is general information. If you have a heart condition or are new to intense exercise, consult a doctor and ease into harder zones.
Is my data uploaded?
No. The calculation happens in your browser.