220 minus Age — the Formula Everyone Uses, and Nobody Derived
The most famous way to estimate max heart rate is 220 − age. It's also the one with the shakiest pedigree: no formal derivation, and a ±10–12 bpm spread.
"220 − age" is everywhere — on treadmills, in apps, on gym posters. Yet it was never derived by regression or published as a validated equation; it's a 1970s rule of thumb drawn through a few small datasets. It's fine as a rough glance, but its ±10–12 bpm error makes it a poor base for training zones. WIMSTA shows it beside eight formulas that were derived, as a range.
"220 − age" gives one tidy number, but its published error is ±11 bpm — your real maximum could be anywhere in that shaded band (169–191). It was never derived statistically; it's a 1970s rule of thumb. The calculator shows it beside eight formulas that were, as an honest range.
The most-cited formula in fitness has no derivation
"220 − age" is usually attributed to Fox, Naughton and Haskell (1971), who sketched an approximate line through about ten small, mismatched datasets — not a statistical fit. In 2002, Robergs and Landwehr reviewed it and concluded it has no scientific basis and shouldn't be used for prescribing exercise. None of that stopped it becoming the default the whole industry repeats.
That's the pattern WIMSTA exists to push back on: the most-repeated number isn't always the best-sourced one. We keep 220 − age visible — but with its real spread, next to formulas that earned their place.
Fine for
A quick, rough ballpark of max heart rate when you don't need precision.
Not for
Training zones — ±10–12 bpm moves every zone. Use Tanaka (or Gulati for women), and read a range.
Don't build zones on one shaky number.
The calculator runs 220 − age beside eight derived formulas, shows the honest range, and turns a better anchor into five training zones.
Open the heart-rate calculatorFox, Naughton & Haskell (1971) — no strict primary derivation. 220 − age · SD ±10–12 bpm. Reviewed as unfounded by Robergs & Landwehr (2002), J Exerc Physiol 5(2):1–10. Kept in the range for transparency, shown with its spread; implementation covered by our test suite.
FAQ
Where does "220 minus age" come from?
It is usually traced to Fox, Naughton and Haskell (1971), who drew an approximate line through a handful of small, disparate datasets. It was never derived by regression or published as a validated equation — a 2002 review (Robergs & Landwehr) concluded it has no scientific basis. Despite that, it became the most-cited formula in fitness.
Why is 220 − age inaccurate?
Two reasons. It was never statistically fitted, and its error is large: the standard deviation is ±10–12 bpm, so your true maximum can sit a dozen beats either side of the number. It also tends to overestimate in younger people and underestimate in older ones.
Is 220 − age good enough?
As a rough ballpark for a casual glance, it is fine. For setting training zones it is not — a dozen beats moves every zone, so you can end up training in the wrong one. Use a formula that was actually derived, and read it as a range.
What should I use instead?
For the general population, Tanaka (208 − 0.7 × age) is the recommended replacement; for women, Gulati (206 − 0.88 × age). Better still, look at the range across several formulas rather than any single number — that is what WIMSTA shows.
How every formula is sourced: the method page.