Heart Rate Zone Calculator
Heart rate zones can be set as plain percentages of your maximum or on your heart rate reserve — the gap between resting and maximum — and the two give noticeably different easy zones. This computes both, and checks something a surprising number of zone tables get wrong: each zone must start exactly where the one below it ends, with no beat falling into a gap between them.
What this generator does
Estimates your maximum from 220 minus your age, then sets five zones either as percentages of that maximum or as percentages of the reserve above your resting rate. The zones are checked to meet exactly and to reach the maximum at the top.
How to use this tool
- Enter your age and your resting heart rate.
- Choose the method — reserve is usually the more useful.
- Read the five zones.
- Compare the methods: the easy zones differ most.
Understanding the controls
- Age
- Used only for the maximum estimate. That estimate is a population average with a standard deviation of around ten beats, so treat it as a starting point rather than your number.
- Resting heart rate
- Measured lying still, ideally on waking. It matters only for the reserve method, where it makes a substantial difference.
- Method
- Reserve — the Karvonen method — accounts for fitness and usually gives higher, more realistic easy zones. Percentage of maximum is simpler and ignores your resting rate entirely.
Common use cases
- Setting training zones for a heart rate monitor
- Comparing the reserve method against plain percentages
- Finding a realistic easy zone rather than one that feels too slow
- Explaining why two calculators give different zone two figures
- Producing a zone table for a training plan
How this generator works
The maximum comes from the familiar 220-minus-age estimate. Percentage-of-maximum zones are straight fractions of it. Reserve zones are fractions of the gap between resting and maximum, added back to the resting rate, which is why they sit higher. Before display each zone is recomputed from its own percentages, every zone is confirmed to start exactly where the one below it ends, and the top zone is confirmed to reach the maximum — a table with a gap between zones is the failure this guards against.
Randomness and fairness
Nothing here is random. An age, a resting rate and a method give exactly one table. Nothing here is medical or coaching advice; these are arithmetic models, and how you train is a matter for you and anyone qualified you ask.
For how randomness is produced across the whole site, see how Generate Random works.
Limitations and good to know
- 220 minus age is a rough population estimate with a spread of about ten beats either way — a measured maximum from a proper test is far better.
- Five zones is one convention among several; some systems use three and others seven, with different boundaries.
- Heart rate lags effort, drifts upwards in heat and over long efforts, and is affected by caffeine, illness and sleep.
- Zones describe intensity, not what training to do with it.Nothing here is medical or coaching advice; these are arithmetic models, and how you train is a matter for you and anyone qualified you ask.
Privacy and your data
The zones are computed in your browser. Your age and resting rate are never transmitted, stored or included in analytics.
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