Heart Rate Zone Calculator

How to use the heart rate zone calculator

1. Fill in the fields — they start with a worked example.
2. Read the answer, and the arithmetic shown beneath it.
3. Copy the results, or adjust the inputs to compare scenarios.

About this tool

Zones are calculated with the Karvonen method, which works from heart rate reserve — the gap between resting and maximum — rather than from maximum alone. It accounts for fitness: two people the same age with different resting rates get different zones, which is the point.

Maximum heart rate is estimated as 208 − 0.7 × age, a formula that fits measured data better than the familiar 220 − age, particularly for older adults. Both are estimates: individual maxima vary by around ±10 beats either way, so treat the boundaries as approximate.

Common uses

• Setting training zones for a heart rate monitor.
• Checking whether an easy run is genuinely easy.
• Understanding what a zone number on a watch means.

Frequently asked questions

Why not 220 minus age?

It is memorable but a poor fit, especially past 40. 208 − 0.7 × age matches measured data more closely, though both are population averages.

How do I find my resting heart rate?

Measure it on waking, before getting up, over several mornings. A wearable's overnight low is a reasonable substitute.

Is this medical advice?

No. If you have a heart condition or are starting exercise after a long break, talk to a clinician about safe intensity.