Heart Rate Zone Calculator

Nobody knows your maximum heart rate

Every number this page produces hangs off a single estimate, and that estimate is not a measurement of you. It is a line drawn through the maxima of thousands of other people, and your own value sits somewhere in the cloud around that line. The scatter is large: about 10 to 12 beats per minute for one standard deviation, which puts a rough 95% interval at roughly ±24 bpm.

Made concrete: a 40-year-old is told their maximum is 180. Both the classic formula and Tanaka’s agree on that figure at exactly this age. The honest reading of it is somewhere between about 156 and 204. A person at each end of that range is perfectly ordinary — not an outlier, not unwell, not mismeasured. Two 40-year-olds of identical fitness can have maxima 40 beats apart, and no equation taking only a birth year as input can tell them apart.

That uncertainty propagates straight into the zones. Take the 35-year-old in the default example, whose estimated maximum is 184 and whose zone 2 therefore runs 110 to 129 bpm. If their true maximum is 160, zone 2 is really 96 to 112. If it is 208, zone 2 is really 125 to 146. The band labelled “easy aerobic” could honestly start anywhere from 96 to 125. That is not a rounding difference; it is the difference between a recovery jog and a tempo effort.

So what is the table for? It is a starting point and a common vocabulary — a way to describe an intended effort before you have better information. Two things beat it, and both are available to anyone:

• A measured maximum. A supervised graded exercise test gives you the real figure. Failing that, the highest heart rate you have genuinely seen at the end of a hard race or a maximal field effort — not a spike from a wet chest strap or an optical sensor catching your cadence — is far better than any equation.
• Your own perception. Whether you can speak in full sentences, in short phrases, or not at all separates easy from moderate from hard more reliably than a formula-derived boundary does, and it costs nothing and needs no device. Every zone description in the table above is written to be checkable that way on purpose.

This is general information, not medical advice

This page does arithmetic on published equations and explains where they came from. It is general educational information about a training convention. It is not medical advice, it is not a diagnosis, and it cannot account for anything about you that an age and a resting pulse do not capture.

Three situations deserve a conversation with a clinician before you use any of this.

• If you take beta-blockers or another rate-limiting medicine. This is the case most often left unsaid, and it is the most consequential. Beta-blockers blunt the heart’s response to adrenaline, lowering both resting and maximum heart rate — often substantially. An age-based maximum is therefore wrong for you, and every zone below it is wrong by the same margin. Chasing a target of 147 bpm that your medicated heart cannot reach means working far harder than intended to hit a number that no longer means what the table thinks it means. The same caution applies to some calcium-channel blockers, to amiodarone, and to pacemakers with a programmed upper rate. Ask the prescriber how to gauge effort instead.
• If you have a known cardiac condition — arrhythmia, coronary disease, cardiomyopathy, a valve problem, an implanted device — or symptoms that might be one: chest pain or pressure on exertion, unexplained breathlessness, palpitations, light-headedness, or fainting. Zone 4 and zone 5 targets ask you to work near the top of your capacity, and that is precisely when an undiagnosed problem shows itself.
• If you are new to vigorous exercise, significantly deconditioned, pregnant, or returning after an illness or a long layoff. The zones are not wrong for you, but the sensible starting point usually is not zone 4 intervals, and someone who knows your history can say so with more authority than a web page.

Nothing here is urgent enough to skip that conversation. Training will still be there next week.

Three estimates of the maximum, two ways to slice it

The maximum comes first, because everything else is a fraction of it. All three equations take age and nothing else.

The three diverge in a way worth noticing. They cross near age 40, where the classic formula and Tanaka’s both give 180. Below that crossing the classic formula reads high — 195 against Tanaka’s 190.5 at age 25. Above it the classic formula reads low, and increasingly so: 155 against 162.5 at age 65. That divergence with age is the specific failure Tanaka’s equation was published to fix, and it is why an older adult training to 220 − age is likely to be undertraining.

Then the zones, in whichever of the two conventions you choose.

Two implementation choices worth stating. The zone bounds are computed from the rounded maximum, the same whole number shown above them, so the table can be checked by hand — multiply the 184 on screen by 0.6 and you get the 110 beside it. And the Karvonen columns return nothing at all when no resting rate has been entered, rather than filling in a population average: a guessed resting rate shifts every zone floor by tens of beats while looking exactly as precise as a measured one.

A 35-year-old with a resting rate of 60, both ways

Start with the maximum. Tanaka gives 208 − 0.7 × 35 = 208 − 24.5 = 183.5, printed as 184. The classic formula gives 220 − 35 = 185. Gulati gives 206 − 30.8 = 175.2, printed as 175. Ten beats separate the highest and the lowest, which is less than one standard deviation of the individual scatter around any of them — a useful reminder that arguing about which formula to use is a smaller question than it feels.

Now zone 2, the endurance band, by percentage of maximum: 184 × 0.60 = 110.4 and 184 × 0.70 = 128.8, so 110 to 129 bpm.

The same zone by Karvonen. Heart-rate reserve is 184 − 60 = 124 beats. The bottom of the band is 60 + 124 × 0.60 = 134.4 and the top is 60 + 124 × 0.70 = 146.8, so 134 to 147 bpm. That floor sits 24 beats above the percentage-of-max floor for the same person, the same zone number and the same label. A plan written in one convention and executed in the other is not slightly off; it is a different session. Whichever you pick, pick one and stay with it.

Finally, the honest version of the first line. That 184 carries an interval of roughly 160 to 208. Run zone 2 at each end and it spans 96 to 112 bpm at the bottom of the interval and 125 to 146 at the top. The arithmetic above is exact; the input it starts from is not.

Five bands, and what each is actually for

The five-zone model is a coaching convention, not a physiological map. Nothing measurable happens to a body at exactly 70% of maximum; the boundaries are round numbers chosen because a continuous scale is hard to talk about. The edges are shared — the top of zone 2 and the bottom of zone 3 are the same beat — and treating them as walls is a misreading.

• Zone 1, recovery (50–60%). Warm-ups, cool-downs, and the genuinely easy days that make hard days possible. Conversation is effortless.
• Zone 2, endurance (60–70%). The aerobic base, and where most of a well-built week sits. It should feel almost too easy; the most common training error by a wide margin is running this zone too hard, which turns an easy day into a mediocre moderate one and leaves nothing for the hard day.
• Zone 3, tempo (70–80%). Steady, uncomfortable, sustainable for a while. Useful in its place, and the easiest place to accidentally spend every single session — hard enough to accumulate fatigue, not hard enough to drive the adaptations zone 4 and 5 do.
• Zone 4, threshold (80–90%). Around the intensity where lactate production starts to outrun clearance. Intervals measured in minutes, with real recovery between them.
• Zone 5, VO₂ max (90–100%). Short, hard efforts sustainable for a few minutes at most. Worth doing on top of an aerobic base, and largely wasted without one.

One practical caveat on reading a monitor: heart rate lags effort by tens of seconds, so it is a poor guide during short intervals — by the time the number arrives, the interval is over. It also drifts upward over a long steady effort at constant pace, a normal response to heat and fluid loss rather than a sign of working harder. For anything under about three minutes, pace, power or perceived effort will serve you better than the number on your wrist.

What this calculator assumes

• Your maximum heart rate follows the population average for your age. It very likely does not — the individual scatter is about ±12 bpm at one standard deviation, and roughly ±24 across a 95% interval.
• You are not taking beta-blockers or another rate-limiting medicine, and do not have a pacemaker with a programmed upper rate. Any of those invalidates every figure on this page.
• The five-zone, ten-percentage-point model is the one you want. Three-zone, six-zone and seven-zone schemes all exist and all draw their lines elsewhere; a zone number only means something alongside the system it came from.
• For Karvonen, that your resting heart rate was measured properly — lying still on waking, averaged over several mornings — rather than taken at a desk after coffee.
• Nothing is adjusted for heat, humidity, altitude, dehydration, caffeine, illness, sleep debt, or cardiac drift over a long session. Each of those moves heart rate at a given effort by more than the difference between the three formulas here.
• Zone boundaries are conventions, not thresholds. Lactate threshold and ventilatory threshold are measured quantities that sit at different percentages in different people, and this page does not estimate either.
• Ages are whole years, and rates are whole beats per minute. No monitor reports a fraction of a beat, and the equations do not deserve one.

Heart rate zone FAQ

Sources and review notes

1. Tanaka H, Monahan KD, Seals DR. “Age-predicted maximal heart rate revisited.” Journal of the American College of Cardiology, 2001 — the source of 208 − 0.7 × age, of the finding that 220 − age underestimates maximum heart rate in older adults, and of the scale of the individual scatter
2. Gulati M, Shaw LJ, Thisted RA, Black HR, Bairey Merz CN, Arnsdorf MF. “Heart rate response to exercise stress testing in asymptomatic women: the St. James Women Take Heart Project.” Circulation, 2010 — the source of 206 − 0.88 × age and of the observation that the standard equations overestimate peak heart rate in women
3. American Heart Association — target heart rate guidance, for the moderate and vigorous intensity ranges the zone bands here are built around

The arithmetic on this page is exact and has nothing behind it to go stale. What can move is the evidence: the age coefficients are regression estimates from particular cohorts, and a future population study could shift them by a beat or two. It would not change the conclusion. The individual scatter around every one of these lines is far larger than the distance between the lines, and that is the fact the page is built to convey.