How to Calculate Your Max Heart Rate (and Why 220 Minus Age Is Rough)

The standard formula for max heart rate is 220 minus your age in years. For a 35 year old, that works out to 220 minus 35, or 185 beats per minute. It is the number printed on most gym cardio machines and the starting point most training plans use to set heart rate zones, and its main appeal is that it requires nothing but your age.

Two more refined formulas track measured max heart rate more closely across a broader range of ages. The Tanaka formula is 208 minus 0.7 times your age: for that same 35 year old, 208 minus (0.7 times 35, or 24.5) comes out to about 183 beats per minute, close to the 220-minus-age result at this age but increasingly different as age climbs. The Gulati formula, derived specifically from a female research cohort, is 206 minus 0.88 times age: for a 35 year old woman, 206 minus (0.88 times 35, or 30.8) gives roughly 175 beats per minute, noticeably lower than either general formula.

All three are estimates built from population averages, not a measurement of your individual physiology. They are useful for a first pass at setting training zones, but none of them account for your fitness level, genetics, or how your heart actually responds under real load.

Using 220 minus age as the reference, estimated max heart rate runs roughly as follows: about 200 beats per minute at age 20, 195 at age 25, 190 at age 30, 185 at age 35, 180 at age 40, 175 at age 45, 170 at age 50, 165 at age 55, 160 at age 60, 155 at age 65, and 150 at age 70. The pattern is a steady decline of about one beat per minute per year, which is where the simplicity of the formula comes from.

None of those numbers are a personal ceiling. The formula carries a standard deviation of roughly plus or minus 10 to 12 beats per minute, so at any given age, a meaningful share of people have a true max 10, 15, even 20 beats above or below the estimate. Fitness level plays a role, highly trained endurance athletes sometimes show a slightly lower max heart rate than untrained peers of the same age, while genetics, altitude exposure, and heat acclimation can all shift an individual's true number in either direction. Age alone explains a lot of the variation between people, but it does not explain all of it, or even most of it for any single person.

The 220-minus-age formula traces back to a 1970s-era analysis of a relatively small, non-representative sample, not a large controlled study designed to nail down individual variation. It was never intended as a precision tool, it was a quick clinical rule of thumb that happened to stick because it is so easy to calculate, and it has been repeated in gyms, fitness trackers, and training plans ever since largely on the strength of that simplicity rather than its accuracy.

In practice, it tends to systematically overestimate max heart rate in younger, highly trained athletes and underestimate it in older adults, which is exactly the gap the Tanaka and Gulati formulas were built to close. The real gold standard is a lab-based VO2 max or graded exercise test, where heart rate is measured continuously to true exhaustion under controlled conditions. Most people never need that level of precision, though, and the practical middle ground that serious runners and coaches actually use is the highest heart rate observed during a genuinely maximal field effort, which is far cheaper than a lab test and considerably more accurate than any formula.

A single unusually high reading is not your max. Heart rate spikes from stress, dehydration, caffeine, heat, or a bad night's sleep can all push a reading higher than what your heart can actually sustain under a true maximal effort, so one outlier data point should not reset your training zones. The number that matters is the peak recorded during genuinely hard, sustained exertion, the last rep of an all-out interval set or the final kick of a competitive race, not a random moment during an easy run. Runners who log hard efforts through Strava already have that peak sitting in their run history, since every logged run carries a continuous heart rate trace rather than a single end-of-workout number.

Tracked across several hard efforts over weeks or months, that peak tends to be far more stable than day-to-day heart rate variability suggests, and it is the number worth anchoring your zones to. Treat it as an input for setting training zones, like Zone 2 aerobic work or lactate-threshold intervals, rather than a target to chase every session; hitting your actual max repeatedly in training is neither necessary nor advisable for most training goals, it is a reference point, not a workout objective.

Start with 220 minus age, or the Tanaka or Gulati formula, for a reasonable first estimate of your training zones. Then let real effort data refine it: the highest heart rate you actually hit during a hard interval set or a race is a far better personal number than any formula, and it is the number that should end up driving your zones once you have it. From there, an AI running coach can turn that observed max into actual zone-based session plans instead of leaving it sitting unused in a chart.