What this estimate does not cover
How to use this calculator
- Choose % of max for the simple version, or heart rate reserve if you know your resting rate.
- Enter your age. If you chose reserve, enter your resting heart rate too.
- Read the five zones, with the beats per minute for each.
- Copy the link to keep this exact set of zones.
Heart rate reserve, usually credited to Karvonen, works from the difference between your maximum and your resting rate rather than from percentages of the maximum alone. It tends to track true training intensity more closely, especially at the easy end, which is why it is worth measuring your resting rate in the morning before you get out of bed.
The formula
The zones are the ACSM's own percentages, not the 50/60/70/80/90 scheme that appears on most gym walls. The ACSM bands are: very light under 57%, light 57–63%, moderate 64–76%, vigorous 77–95%, and near maximal 96% and above.
Why not 220 − age
It is worth being precise, because the number is genuinely useful as an illustration of how a formula acquires authority it has not earned.
The 1938 paper people cite it to, by Robinson and colleagues, published 212 − 0.7 × age, not 220 − age. The 220 form appears in a 1971 review by Fox, Naughton and Haskell, which fitted no regression of its own and presented the number as a convenience approximation. Nobody has traced an original derivation for it.
In 2002 Robergs and Landwehr went back to the underlying measurements, re-fitted the data, and got 215.4 − 0.9147 × age with a standard error near 21 b/min. Their conclusion was blunt: the familiar equation has "no scientific merit" for predicting an individual's maximum. The ACSM does not endorse a universal age-based equation for individuals either.
Tanaka and colleagues published 208 − 0.7 × age in 2001. They built it by collecting group-mean maximum heart rates from 351 studies, 492 groups and 18,712 subjects, then cross-validated the equation in a controlled laboratory study of 514 healthy people, where their own regression came out at 209 − 0.7 × age — effectively identical. The line did not differ between men and women, and habitual activity level did not move it.
The same authors noted explicitly that the familiar equation underestimates maximum heart rate in older adults, which matters: prescribing exercise at 85% of a 220 − age maximum asks a 70-year-old for a load they may not tolerate.
Source
Tanaka, H., Monahan, K. F., & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1), 153–156. PMID 11153730.
Zone percentages: American College of Sports Medicine (2011). ACSM's Guidelines for Exercise Testing and Prescription, 9th edition, and the ACSM position stand in Medicine & Science in Sports & Exercise 43(7):1334–1359. The ACSM does not endorse a single universal age-based HRmax equation for individuals, which is why the bands here are applied to a predicted maximum and the prediction is labelled as one.
Population covered: healthy adults, drawn from published group means rather than measured individually, then confirmed in a laboratory study of 514 healthy volunteers. The regression was identical for men and women and unaffected by habitual activity level. It is not applicable to children, to elite athletes whose maxima may run above the line, or to anyone with a heart condition.
Frequently asked questions
Is Tanaka better than 220 − age?
Yes. It is a real regression, cross-validated against a laboratory study, where 220 − age is a convenience approximation that was never derived from anything. It is still a population average, and an individual can sit well either side of it.
What is my actual max heart rate?
Only a graded exercise test can tell you. Measuring it once removes the guesswork from every zone on this page.
Why is there no zone for children?
The equation and the bands are published for adults 18 and over. They are not validated for younger people.