Heart Rate Zone Calculator
Calculate five training zones from age or a measured maximum heart rate. Compare percentage-of-maximum zones with the heart rate reserve method, select a target zone, and see its midpoint in beats per minute.
| Zone | Intensity | Heart rate range | Midpoint |
|---|
How to calculate heart rate zones
Choose how maximum heart rate is obtained. A measured maximum from an appropriate supervised test is specific to the individual; age formulas are population estimates. Then choose either simple percentages of maximum heart rate or heart rate reserve, which incorporates resting heart rate.
Example: at age 40, the Tanaka estimate is 208 − (0.7 × 40) = 180 bpm. With percentage-of-maximum zones, Zone 2 is 108–126 bpm. With a resting heart rate of 60 bpm, heart rate reserve is 120 bpm and Zone 2 becomes 132–144 bpm.
Bounds are rounded to the nearest whole beat per minute. Adjacent zones share their boundary; wearable devices can differ by one beat because of rounding or proprietary zone definitions.
Formulas and five-zone model
- Tanaka age estimate: maximum heart rate = 208 − 0.7 × age.
- Traditional age estimate: maximum heart rate = 220 − age.
- Heart rate reserve: HRR = maximum heart rate − resting heart rate.
- Karvonen target: target bpm = resting heart rate + intensity × HRR.
The five zones use 50–60%, 60–70%, 70–80%, 80–90%, and 90–100%. These are general planning bands, not universal physiological thresholds. A laboratory or field assessment may define different zones for running, cycling, medication use, or a specific training system.
Formula references: Tanaka, Monahan and Seals (2001) for the age-predicted maximum, and Karvonen, Kentala and Mustala (1957) for heart-rate-based training intensity.
Limits and safe use
This calculator is educational and is not a medical assessment. Age-predicted maximum heart rate has substantial individual error, and optical wrist sensors can lag or misread. Do not use a calculated number to ignore symptoms or medical advice.
Ask a qualified clinician before changing exercise intensity if you have cardiovascular or respiratory disease, are pregnant, take medication that affects heart rate, have been advised to limit exercise, or develop chest pain, faintness, unusual shortness of breath, or palpitations.