Heart Rate Zones Calculator

Heart rate training splits effort into five bands — recovery, endurance, tempo, threshold and maximum — and the tool prints all five in beats per minute for your age and resting rate. Two choices decide the numbers, and both matter more than the zone names do.

The first is which maximum-heart-rate estimate to use. The famous 220 − age has no research behind it; it was an eyeball line drawn through scattered data in the 1970s and it is wrong in opposite directions at either end of the range. Tanaka's 208 − 0.7 × age, fitted to a meta-analysis of real measurements, agrees with it exactly at age 40 and diverges from there: at 20 it gives 194 against 200, at 70 it gives 159 against 150. Gulati's 206 − 0.88 × age was derived from a large cohort of women and runs lower still — 162 at age 50 where 220 − age says 170. Whichever you pick, the spread between individuals of the same age is roughly ten beats either side, so your own maximum can sit twenty beats away from every formula here. A number measured in a hard field test beats all three.

The second choice is the percentage method, and it shifts the zones further than the formula choice does. Straight percent-of-maximum scales the whole range from zero, while the Karvonen method scales the reserve between your resting and maximum rates. For a 40-year-old with a maximum of 180 and a resting rate of 50, the 70 percent line falls at 126 beats with percent-of-maximum and 141 with Karvonen — a fifteen-beat gap, wider than an entire zone. Neither is wrong; they are different scales, so never compare a zone from one against a plan written in the other.

Treat the output as a starting frame rather than a prescription. Heart rate lags effort by a minute or two, drifts upward over a long session at constant power, and moves with heat, altitude, caffeine, illness and sleep. If you are on beta blockers or another rate-controlling medication the arithmetic underneath these zones does not apply at all, and if you have a cardiac condition or are starting from a long layoff, the zone worth training in is the one your clinician names.