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Heart Rate Zone Calculator

Estimate five exercise heart-rate zones from an age-based maximum or a maximum you already know. Choose percentage-of-maximum or Karvonen reserve, then adjust each zone boundary.

Zone boundary percentage

Set six strictly increasing cutoffs from 0 to 100%. They create five adjacent zones; start with the defaults or customize them.

A common estimate is maximum heart rate ≈ 220 − age, but it is not a measurement and can differ substantially for an individual. The default 50–100% cutoffs are only an editable partition, not a recommendation or the AHA target range; AHA describes a general target of about 50–85% of estimated maximum for moderate-to-vigorous activity.

Medicines and health conditions can change heart-rate response. If you have a heart condition, take medicine that affects heart rate, are pregnant, are under 18, or need a personal exercise target, ask a qualified health professional. Stop activity and seek appropriate help for concerning symptoms. The CDC talk test is another way to judge relative effort.

All inputs stay in this browser; nothing is uploaded or stored.

Sources: American Heart Association: target heart rates · CDC.

How do I calculate heart rate zones?

Choose a method and six increasing percentage boundaries. Percentage-of-maximum multiplies your maximum heart rate by each cutoff. Karvonen adds that percentage of heart-rate reserve (maximum minus resting heart rate) to your resting rate. The age estimate uses 220 minus age; it is only a rough population estimate.

Frequently asked questions

How do I calculate heart rate zones?

Choose a method and six increasing percentage boundaries. Percentage-of-maximum multiplies your maximum heart rate by each cutoff. Karvonen adds that percentage of heart-rate reserve (maximum minus resting heart rate) to your resting rate. The age estimate uses 220 minus age; it is only a rough population estimate.

Are my heart-rate inputs saved?

No. The calculation runs in this browser. Your age, heart rates and zone cutoffs are not uploaded or saved by this tool.

What is the Karvonen formula?

It estimates a target rate as resting heart rate plus a chosen fraction of heart-rate reserve. Reserve is maximum heart rate minus resting heart rate. This result is still an estimate, not an individualized prescription.

Is 220 minus age an exact maximum heart rate?

No. It is a rough age-based population estimate cited by the American Heart Association, not a measurement of your own maximum. Fitness, health, medication and individual variation can affect heart rate.

Are heart-rate zones medical limits?

No. These ranges are configurable arithmetic estimates for general education. A clinician can help set personal targets, especially with a heart condition or medicine that affects heart rate.