Heart Rate Zone Calculator
Calculate your maximum heart rate and training zones from age, using the Tanaka or Fox formula, with the Karvonen method if you add resting heart rate.
Written by Rahman · Last reviewed
Quick answer
Maximum heart rate is commonly estimated as 208 − (0.7 × age), the Tanaka formula, from a 2001 meta-analysis of over 18,000 subjects, or the older, less accurate 220 − age rule. Training zones are then set as percentages of that maximum, or of heart rate reserve (the Karvonen method) if a resting heart rate is provided. Both formulas are population averages: an individually measured maximum can differ from either prediction by a meaningful margin.
| Zone | % of max HR | Target bpm |
|---|---|---|
| Zone 1 — Very light | 50–60% | 92–110 bpm |
| Zone 2 — Light | 60–70% | 110–128 bpm |
| Zone 3 — Moderate | 70–80% | 128–147 bpm |
| Zone 4 — Hard | 80–90% | 147–165 bpm |
| Zone 5 — Maximum | 90–100% | 165–184 bpm |
Add your resting heart rate to switch to the Karvonen (heart rate reserve) method, which some find more individually accurate. Age-based maximum heart rate formulas carry real individual variation — a measured max can differ from either prediction by a meaningful margin in either direction.
Results are general screening estimates, not medical advice or a diagnosis. They can read inaccurately for athletes, older adults, children and during pregnancy. Speak to a doctor or registered dietitian before changing your diet, exercise or medication.
About the Heart Rate Zone Calculator
Heart rate training zones divide effort into bands (typically five, from very light to maximal), expressed as a percentage of an estimated maximum heart rate. They are widely used to structure endurance and cardio training by intensity rather than by pace or power alone.
This calculator estimates maximum heart rate from age using either the Tanaka or the traditional Fox formula, and computes the five zones either as a straight percentage of that maximum or, when a resting heart rate is supplied, using the Karvonen heart-rate-reserve method.
Tanaka: HRmax = 208 − (0.7 × age) Fox (traditional): HRmax = 220 − age Karvonen (reserve): Target = ((HRmax − resting HR) × zone%) + resting HR
The Tanaka formula comes from a meta-analysis of 18,712 subjects across 351 studies (Tanaka, Monahan & Seals, 2001); the Fox formula (220 − age) has no equivalent published derivation and is now considered less accurate, particularly for older adults, where it underestimates true maximum heart rate.
Why the formula you use matters more with age
The two formulas agree closely for a young adult but diverge as age increases, because 220 − age falls faster than 208 − 0.7 × age. At age 60, Fox predicts 160 bpm while Tanaka predicts 166 bpm, a 6 bpm gap that shifts every zone boundary computed from it. The 2001 study that introduced the Tanaka formula found the older 220 − age rule specifically underestimates maximum heart rate in older adults, which understates both the true intensity of an exercise test and the appropriate intensity of a prescribed training zone.
Reading the result as a range, not a target
Both formulas are population averages fitted to age alone; real individual variation around either prediction is substantial, and a directly measured maximum heart rate (from a supervised maximal exercise test) will often differ from either age-based estimate. Zones computed here are a reasonable starting point for structuring training, not a substitute for a measured value if one is available.
Frequently Asked Questions
Which formula is more accurate, Tanaka or Fox (220 − age)?
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Tanaka (208 − 0.7 × age) is the better-supported formula, derived from a large meta-analysis and validated in a separate laboratory sample. The traditional 220 − age rule has no equivalent published derivation and is now understood to underestimate maximum heart rate, especially in older adults.
What is the Karvonen method?
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It calculates target heart rate from heart rate reserve (the gap between your maximum and resting heart rate), rather than from maximum heart rate alone, which accounts for individual fitness level via resting heart rate.
Should I train in a specific zone?
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Different zones serve different training goals, and the right mix depends on your sport, fitness level and program; this calculator reports the zones themselves rather than prescribing which one to train in.
Why does my measured heart rate differ from the calculated maximum?
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Age-based formulas are population averages. Genetics, fitness level and how maximum heart rate was measured all produce real individual variation around any age-based prediction.
Sources
- Tanaka, Monahan & Seals (2001) — Age-predicted maximal heart rate revisited — The meta-analysis and validation study establishing the 208 − 0.7 × age formula, and its finding that 220 − age underestimates HRmax in older adults.