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Heart Rate Zone Calculator

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Training zones only mean something once you know which maximum and which method produced them, because the two common approaches can differ by more than twenty beats. This shows both, names the formula behind each, and states how wide the uncertainty really is.

From a meta-analysis of 351 studies. A better fit across the age range than 220 − age.

Divide the range by

Optional — used only to show what Karvonen would have given instead.

How to use the heart rate zone calculator

  1. 1Enter your age, or your maximum heart rate if you have measured it in a proper test.
  2. 2Pick which estimate to use when you have not — Tanaka is the better-supported one.
  3. 3Add your resting heart rate to use the Karvonen reserve method, which most coaching plans assume.
  4. 4Compare the two methods before settling on a set of numbers to train by.

Examples

Age 40, resting rate 60, Karvonen

Input
Tanaka maximum of 180, heart rate reserve of 120
Result
Zone 1 120-132, zone 2 132-144, zone 3 144-156, zone 4 156-168, zone 5 168-180 beats per minute.

By percentage of maximum instead, zone 2 would be 108-126 — a 24-beat difference at the bottom of the zone.

Comparing the estimates

Input
Age 40 across the three formulas
Result
Tanaka 180, the old 220-minus-age 180, Gulati 170.8. They coincide near 40 and diverge sharply at either end of the age range.

About the heart rate zone calculator

Why 220 minus age refuses to die

It is memorable, it needs no calculator, and it is roughly right in middle age — which is enough to keep a bad formula in circulation for fifty years. Its origin is a 1971 review that plotted data from a handful of studies and drew a line through it by eye; the authors did not present it as a validated equation and later said as much.

The error is systematic rather than random. It runs low for older adults and high for younger ones, so a 25-year-old given 195 may have a genuine maximum near 200, and a 65-year-old given 155 may reach 165. Tanaka's shallower slope of 0.7 beats per year fits the measured data considerably better across the whole range, which is why it has become the standard recommendation.

Perceived effort is the check on the arithmetic

Every number on this page rests on an estimate with a wide margin, so the sensible way to use them is as a starting point that gets corrected by how the training actually feels. The talk test is the standard cross-check: full sentences in zone 2, short phrases at threshold, single words at maximum.

When the numbers and the sensation disagree, the sensation is more likely to be right about you than a population formula is. Heart rate also drifts upward over a long session at constant effort, rises in heat, and responds to sleep, illness, caffeine and stress — so a rate that means zone 2 on one day means something harder on another. Treat the zones as a guide and let the perceived effort govern.

Frequently asked questions

Which maximum heart rate formula should I use?
Tanaka, unless you have a measured figure. The familiar 220-minus-age was never derived from a proper study — it came out of a rough fit to scattered data in the 1970s — and it understates the maximum for older people and overstates it for the young. Tanaka's 208 minus 0.7 times age comes from a genuine meta-analysis. Gulati's is derived from women specifically and typically returns a lower figure.
How wrong can an age-based estimate be?
Wider than a training zone. The spread around these formulas is roughly plus or minus 11 beats per minute at one standard deviation, so a substantial share of people sit more than a zone away from the estimate for their age. Maximum heart rate is largely genetic and barely responds to fitness, which is why a fitter person does not have a higher one — they do more work at the same rate.
What is the difference between Karvonen and percentage of maximum?
Percentage of maximum takes a share of the maximum itself. Karvonen works from the reserve — the gap between resting and maximum — and adds the resting rate back on. Karvonen therefore produces higher zone boundaries, and reflects that somebody with a resting rate of 45 is doing far less work at 130 beats than someone whose resting rate is 75. The two are not interchangeable, and mixing them mid-plan is a common way to end up training harder than intended.
Why does zone 2 get so much attention?
Because a large share of endurance training is meant to sit there, and most people train above it. It is easy enough to hold a conversation in full sentences, which is the practical test, and the point is accumulating time rather than effort. The reason it works is a question about physiology rather than arithmetic — but the reason it is missed is nearly always that the zone was calculated from a maximum that was too high.
Is this medical advice?
No. This is arithmetic on the numbers you enter, using published formulas that estimate a population average. It cannot account for medication that alters heart rate, for a heart condition, or for anything else about your individual circumstances. If you have a cardiac condition, take medication affecting heart rate, or are returning to exercise after a break or an illness, speak to a doctor about appropriate intensity before using any of these figures.

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