Heart Rate Zones Calculator
Estimate four heart-rate training bands from age and resting pulse.
On this page
What this calculator estimates
Estimate four heart-rate training bands from age and resting pulse. This page always uses heart-rate reserve, which differs from taking a percentage of maximum heart rate alone.
Inputs and calculation method
Enter age in years and resting heart rate in beats per minute (bpm). The tool estimates maximum heart rate as 220 − age, subtracts resting heart rate to obtain reserve, then adds resting heart rate back after applying each zone percentage. There is no measured-maximum input.
Formula and units
Estimated maximum = 220 − age. Reserve = estimated maximum − resting bpm. Zone boundary = resting bpm + reserve × intensity fraction. The four displayed bands are 50–60%, 60–70%, 70–80% and 80–90% of reserve, rounded to whole bpm.
How to use it
- Measure resting pulse while resting, not immediately after exercise.
- Enter age and resting pulse, then calculate.
- Read each band as a percentage of heart-rate reserve.
- Compare the estimate with perceived effort and any individual training or clinical guidance.
Worked example
At age 30 with resting pulse 65 bpm, estimated maximum is 190 and reserve is 125 bpm. Zone 1 is 128–140 bpm, Zone 2 is 140–153, Zone 3 is 153–165 and Zone 4 is 165–178 after rounding.
How to read the result
The 190 bpm maximum in this example is an age-based estimate, not a measured limit. Zone names and boundaries differ between training systems, so check the calculation method before copying these bands into a watch.
Common mistakes
- Entering an exercise pulse as resting heart rate.
- Comparing reserve percentages directly with maximum-heart-rate percentages.
- Treating 220 − age as a precise personal maximum.
Method limitations
Age formulas vary substantially between individuals. Medication and heart conditions can change the relationship between pulse and exertion; use an individually agreed exercise range where applicable.
Sources and method references
Supporting guides for this calculator
Read next
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Heart Rate Zones Calculator FAQs
Can I enter a tested maximum heart rate?
No. This version estimates maximum from age; it does not offer a measured-maximum field.
Why are the bands higher than a percentage-of-max chart?
Heart-rate reserve adds resting pulse after multiplying the reserve. It is a different denominator and gives different bpm values.
Where is Zone 5?
This interface displays four bands ending at 90% of reserve. It does not display a fifth band.
Using the estimate
Use these four reserve-based bands as approximate training references. Keep the method, resting measurement and age assumption visible when comparing them with another tool.