Heart Rate Zone Calculator
Calculate your maximum heart rate and personalised training zones using the Karvonen method.
Last updated · View algorithm, constants and default inputs (JSON)
This estimate uses Tanaka HRmax = 208 − 0.7 × age, then sets zones at 60–70%, 70–80%, 80–90%, and ≥90% of heart-rate reserve (estimated maximum minus resting rate). These are one training model, not measured thresholds or medical advice; medicines and health conditions can change heart rate.
About this calculator
This estimate uses Tanaka HRmax = 208 − 0.7 × age, then sets zones at 60–70%, 70–80%, 80–90%, and ≥90% of heart-rate reserve (estimated maximum minus resting rate). These are one training model, not measured thresholds or medical advice; medicines and health conditions can change heart rate.
Worked example
calculated with the default values below
Age 30 years · Resting heart rate 60 bpm 2 · 60–70% HRR 136 – 149 bpm · 1 · 50–60% HRR 124 – 136 bpm · 3 · 70–80% HRR 149 – 162 bpm · 4 · 80–90% HRR 162 – 174 bpm · 5 · 90–100% HRR 174 – 187 bpm · Maximum heart rate 187 bpm · Zone 2 (aerobic base) from 136 bpm · Zone 2 to 149 bpm · Zone 3 (tempo) from 149 bpm · Zone 4 (threshold) from 162 bpm · Zone 5 (max) from 174 bpm
General background references
Disclaimer
These calculators are for general information only and are not a medical device, a diagnosis or a treatment plan. Reference ranges describe populations, not individuals, and do not account for pregnancy, medication, disability or athletic training. Discuss your own situation with a qualified healthcare professional.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
HR_p = RHR + p×(208 − 0.7×age − RHR)
- age
- Age in years
- RHR
- Resting heart rate
- p
- Zone fraction of heart-rate reserve
- HR_p
- Target heart rate
HRmax = 208 − 0.7×age; HR(p) = RHR + p×(HRmax−RHR). p bands: 0.60–0.70, 0.70–0.80, 0.80–0.90, ≥0.90. Population estimate only; not a measured or prescribed target.
Frequently asked questions
Which maximum-heart-rate formula does this use?
It uses the Tanaka estimate, 208 − 0.7 × age, developed as a population estimate for healthy adults. It does not measure your personal maximum; predicted values vary between people.
How are the zones calculated, and why might a watch differ?
The calculator applies 60–70%, 70–80%, 80–90%, and at least 90% to heart-rate reserve (estimated maximum minus resting heart rate). Devices may use different equations or zone models.
Are these medical or individualized training targets?
No. These are general estimates. Medicines and health conditions can affect heart rate; ask a health professional for guidance if you have a heart condition, take medication, or are unsure what intensity is appropriate.