The formula
How to calculate maximum heart rate
Maximum heart rate is the highest rate your heart can reach during all-out effort. It is mostly determined by age and genetics, not by fitness — training makes you faster at a given heart rate rather than raising the ceiling.
The familiar 220 − age rule was never derived from a formal study; it emerged from a rough fit to scattered data in the 1970s. Tanaka's 2001 meta-analysis produced a better fit and is the version most exercise physiologists now use.
What to enter:
- Age (years)
Results appear immediately — there is nothing to submit. Changing a field rewrites the link, so you can share the exact scenario you are looking at.
Consistency in how the underlying measurements are taken matters more than precision to the last decimal — measuring at the same time of day, in the same state of rest or hydration, makes readings taken weeks apart genuinely comparable in a way that a single very precise reading on its own is not.
Why maximum heart rate matters
People usually look up a maximum heart rate calculation to put a number on something they can already sense but cannot quite quantify — how their fitness compares with a reference range, how a measurement is trending, or what a change actually means. A calculator turns that vague sense into a concrete figure, which is useful even though the figure itself is only ever an estimate.
This tends to get checked before or after a change in routine — a new training block, a change in diet, a different stage of a pregnancy — as a way of putting a figure on something that would otherwise only be felt rather than measured.
A single number like this is most useful placed in context rather than read in isolation. Reference ranges exist because bodies vary considerably and still count as healthy across a wide spread of values, so a result sitting outside a commonly quoted range is a prompt to look more closely rather than a verdict on its own. The same figure, tracked consistently over time, tends to say more than any single reading ever will.
In practice, this kind of figure is often calculated more than once with slightly different inputs to see how sensitive it is — trying a measurement taken this morning against one taken yesterday evening, for instance, to see how much normal daily variation actually moves the result. That habit is a good one: it builds a feel for how much a single reading can be trusted on its own before drawing any conclusion from it.
Worked example
Work through the defaults on this page:
- Age: 38 years
That gives:
- Tanaka estimate: 181 bpm
- Classic 220 − age: 182 bpm
- Gulati estimate, women: 173 bpm
Those starting figures exist only to show the calculation working, not as a target or a reference value to compare yourself against — replace them with your own measurements in the calculator above and the same formula applies exactly as shown.
Reading the result
Individual variation is wide — around 10–12 bpm standard deviation at any age. Two 38-year-olds can genuinely have maximums of 175 and 200, so a formula gives you a starting point rather than your number.
Where this goes wrong. Do not attempt a maximal test to find your true figure without medical clearance, particularly over 40 or with any cardiac history. A supervised test is the only reliable way, and it should be supervised for a reason.
As with any general-purpose formula, the result here is an estimate derived from population averages, not a measurement specific to you — a reasonable starting point for a conversation with a qualified professional, not a replacement for one. Nothing on this page is medical advice.
It systematically overestimates for younger adults and underestimates for older ones. Tanaka's formula tracks the actual decline better, though individual variation still dominates.
Essentially no. Training improves stroke volume, lactate threshold and efficiency, which is why you get faster — but the maximum itself is fixed and declines gradually with age.
The answer it gives you is tanaka estimate. With 38 years age, that comes to 181 bpm. Change any field and the figure moves with it.
It uses a published formula applied exactly as defined, so the arithmetic itself is precise — but the formula is a population-level estimate, and individual results can vary from it for reasons the formula has no way to account for. Treat the output as a reasonable estimate rather than a measured or diagnostic value.
For most people, yes — a single reading is a snapshot, while the same measurement repeated consistently over weeks or months shows a trend, which is generally more informative than any one figure taken in isolation.
Small differences between calculators usually come down to which published formula or reference dataset each one uses — several equations in this area exist in more than one accepted version. This page states the specific formula used in the section above, so it is possible to check directly whether another source is using the same one.