Heart Rate Zone Calculator
Calculate five training heart rate zones from age-predicted maximum heart rate (220 − age or Tanaka), optionally with the Karvonen method.
About Heart Rate Zones
Zones are percentages of an age-predicted maximum, which can be off by 10 or more beats per minute for an individual. The Karvonen method applies the percentages to your heart rate reserve (maximum minus resting), so a fitter heart with a low resting rate gets higher targets. If you have a heart condition or take medication that affects heart rate, ask your doctor which targets are safe for you.
Tip: Measure your resting heart rate first thing in the morning before getting out of bed for the most accurate reading.
Updated Formula covered by automated tests
Heart rate zones split the range between an easy jog and an all-out sprint into five bands, so you can tell from a watch or chest strap whether a workout is as easy or as hard as intended. Enter your age and the calculator estimates your maximum heart rate, then lists the beats per minute for each zone from 50% to 100% of that maximum.
You can choose how the maximum is estimated: the traditional 220 minus age, or the 208 minus 0.7 times age equation from Tanaka and colleagues. If you know your resting heart rate, tick the Karvonen option and the zones are built on heart rate reserve instead, which shifts every target upward for people with a low resting pulse.
The formula
- HRmax
- Estimated maximum heart rate in beats per minute (bpm)
- age
- Age in years
- HRrest
- Resting heart rate in bpm, ideally measured on waking before getting out of bed, averaged over several mornings
- HRmax − HRrest
- Heart rate reserve: the span of beats available for exercise above your resting level
- intensity
- Zone boundary as a fraction: 0.5, 0.6, 0.7, 0.8, 0.9 or 1.0
The 220 minus age rule was popularized around 1970 from a simple line drawn through published data, and it was never based on a formal study. In 2001 Hirofumi Tanaka, Kevin Monahan and Douglas Seals pooled 351 studies plus their own laboratory tests and found that 208 − 0.7 × age fits better, especially for older adults. The two formulas give the same answer at age 40 (180 bpm); below that the traditional rule is higher and above it the Tanaka equation is.
Martti Karvonen showed in 1957 that training intensity tracks heart rate reserve more closely than raw heart rate. Using reserve means a well-trained person with a resting rate of 50 and a sedentary person with a resting rate of 80 get different targets for the same zone, even at the same age. The five 10-point bands used here are a common convention in fitness devices; sports scientists also use three-zone models based on lactate or ventilatory thresholds.
Worked example
Grace is 50 and measured a resting heart rate of 60 bpm on three mornings. She wants her Zone 2 and Zone 3 ranges using the traditional formula with the Karvonen method.
- 1 Maximum heart rate: 220 − 50 = 170 bpm.
- 2 Heart rate reserve: 170 − 60 = 110 beats.
- 3 Zone 2 (60% to 70%): 60 + 0.6 × 110 = 126 bpm, up to 60 + 0.7 × 110 = 137 bpm.
- 4 Zone 3 (70% to 80%): 60 + 0.7 × 110 = 137 bpm, up to 60 + 0.8 × 110 = 148 bpm.
- 5 Without Karvonen, Zone 2 would be 0.6 × 170 = 102 to 0.7 × 170 = 119 bpm.
Result: Grace’s Zone 2 is 126 to 137 bpm and Zone 3 is 137 to 148 bpm. With the Tanaka formula her maximum would be 208 − 35 = 173 bpm, raising each boundary by two or three beats.
Before you rely on the result
- Age-predicted maximum heart rate is an average; your true maximum may be well above or below it.
- Heat, dehydration, caffeine, altitude, illness and lack of sleep all raise heart rate for the same effort, so zones are a guide rather than a strict rule on any given day.
- Talk to a healthcare professional before starting vigorous exercise if you have chest pain, dizziness, a heart condition or have been inactive for a long time.
Frequently asked questions
Which max heart rate formula should I pick?
Both are population averages. Tanaka is generally more accurate after middle age, while the traditional rule is easier to remember. Individual maximums commonly differ from either prediction by 10 bpm or more, so a supervised exercise test or a well-paced all-out effort gives a better number for experienced athletes.
Why does my watch show different zone numbers?
Watches and apps may use their own maximum heart rate estimate, a reserve-based method, lactate threshold, or zones that you set manually. Check which basis your device uses before comparing. The numbers here are fixed by the formulas named in the results so you can reproduce them.
Is there a special fat-burning zone?
At low intensity a larger share of the energy you use comes from fat, but you burn fewer total calories per minute. For weight management, total energy spent over the week matters more than the zone. Easy Zone 2 work is valued mainly for building aerobic endurance with little fatigue.
Do these zones apply if I take beta blockers?
No. Beta blockers and some other heart medications lower both resting and maximum heart rate, so age-based zones can be far too high. People taking them, or living with any heart condition, should ask their doctor or a cardiac rehabilitation team for personal targets or use perceived exertion instead.
Sources
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol, 2001 (pubmed.ncbi.nlm.nih.gov)
- American Heart Association: Target Heart Rates Chart (heart.org)