Max Heart Rate Calculator

Where 220 − age came from

It was not derived from an experiment designed to find it. In 1971 Haskell and Fox plotted roughly 35 published data sets — many small, several using unfit or unwell subjects — and drew a line through them by eye. There was no regression, and no reported error term. Fox himself later noted it wasn't meant as a precise clinical tool. It survived because it fits on a gym poster.

The problem is that it isn't just imprecise, it's biased: it overestimates max heart rate in young people and underestimates it in older ones. The two lines cross at exactly age 40, which is why so many 40-year-olds find the formulas agree and assume they always do.

The five formulas

Tanaka — 208 − 0.7 × age. Tanaka, Monahan & Seals, JACC 2001. A meta-analysis of 351 studies covering 18,712 subjects, then validated prospectively. The best general-purpose choice.
Gulati — 206 − 0.88 × age. Gulati et al., Circulation 2010, derived in 5,437 women. Fox systematically overestimates women's max HR, which pushes their training zones too high.
Nes (HUNT) — 211 − 0.64 × age. Nes et al., 2013, 3,320 healthy adults, directly measured rather than pooled.
Åstrand — 216.6 − 0.84 × age. From 1952, still widely cited.
Fox — 220 − age. Included so you can see how far off it drifts.

The number that actually matters

Individual max heart rate scatters around every one of these formulas with a standard deviation of about 10–12 bpm. That means roughly a third of people are more than 10 bpm away from their predicted value, and 1 in 20 is more than 20 bpm away. The disagreement between formulas — around 15 bpm across the whole adult age range — is smaller than the disagreement between you and the average person your age.

So the practical answer: any of these is fine for setting rough zones, Tanaka or Gulati are the defensible picks, and if you're training seriously enough to care about the difference, you need a measured max from a field test or a lab, not a formula.

Worked example

A 30-year-old woman. Fox says 220 − 30 = 190. Gulati says 206 − 0.88 × 30 = 179.6 — over 10 bpm lower. If she sets her threshold intervals from Fox, she's chasing a number she may not possess, and her "easy" zone-2 runs land in zone 3. This is the most common way the old formula quietly wrecks a training plan.

FAQ

How do I measure my real max heart rate?

The standard field test is a long, hard hill effort: warm up thoroughly, then run or cycle uphill at the hardest pace you can hold for about three minutes, recover briefly, and repeat harder. The highest number you see is close to your true max. It is genuinely unpleasant, and it's a bad idea if you have any cardiac risk factors, are over 40 and untrained, or haven't been cleared for maximal exercise. A supervised graded test is the safe version.

Why does my watch show a higher max than these formulas?

Two possibilities. Your genuine max may simply be above average — perfectly common. Or the reading is an artefact: wrist optical sensors are prone to "cadence lock", where they latch onto your arm-swing rate instead of your pulse, and to spikes in cold weather. A chest strap resolves it. If you've seen the same high number repeatedly across different sessions, believe it over the formula.

Does a higher max heart rate mean I'm fitter?

No, and this is the most persistent misconception here. Max heart rate is essentially a fixed personal trait set by age and genetics; training barely moves it, and it declines whether you train or not. Fitness shows up in resting heart rate, in how much oxygen you use at a given heart rate, and in how quickly you recover afterwards — not in how high the number goes.

Which should I use for training zones?

Gulati if you're a woman, Tanaka otherwise — then treat the resulting zones as a starting point and adjust by feel. Better still, base zones on heart rate reserve, which folds in your resting heart rate and is far more personal than max alone. The target heart rate calculator does that.