Heart rate zone calculator: your five training zones by age

Zone 2 at age 40worked example

108-126 bpm

Maximum heart rate used: 180 bpmtanaka equation
Method: percent of maximumadd a resting rate to switch
Same zone from the other equation: 108-126 bpmfox, HRmax 180
Spread across the three HRmax equations: 9 bpm

The five ten-point zones are a training convention, not a published finding, and this page says so where most do not. ACSM's own classification of relative intensity uses different boundaries entirely, so both tables are printed below. Every edge here is a percentage of one estimated number that itself carries roughly 7 to 11 bpm of prediction error, which makes a boundary quoted to the beat false precision.

Your ageResting heart rate (optional)Supplying it switches the zones to Karvonen, which sit higher.

Sex

Which maximum-heart-rate equation should the zones sit on?

Switching this moves every boundary in the table below. That is the point of exposing it.

Your five zones at age 40 (percent of a 180 bpm maximum)
Zone	% of max	Range	ACSM's word for it	What it is used for
Zone 1	50-60%	90-108 bpm	very light	Very light effort - warm-up, cool-down, recovery.
Zone 2	60-70%	108-126 bpm	moderate	Light, conversational effort sustained for long periods.
Zone 3	70-80%	126-144 bpm	moderate	Moderate effort - talking becomes short-sentenced.
Zone 4	80-90%	144-162 bpm	vigorous	Hard effort, sustainable only for shorter intervals.
Zone 5	90-100%	162-180 bpm	vigorous	Maximum effort, held for very short intervals.

Zone 2 is highlighted because it is the band most people arrive looking for. The ACSM column is there to show that the published classification does not line up with the convention: ACSM's moderate band, 64 to 76 percent, straddles Zone 2 and Zone 3.

The intensity classification ACSM actually published (Garber 2011)
ACSM intensity	% of maximum heart rate	At 180 bpm
very light	0 to 56%	0-101 bpm
light	57 to 63%	103-113 bpm
moderate	64 to 76%	115-137 bpm
vigorous	77 to 95%	139-171 bpm
near-maximal to maximal	96% and above	173 bpm and above

From the 2011 ACSM position stand on prescribing exercise. Four boundaries, not five, and none of them at a round ten.

Minutes per week you spend in Zone 2 (optional)Saved to your Numbers Log so you can watch it across quarters.

Every single year from 20 to 70, plus 75 and 80, has its own page with the equations worked out for that age. For example age 30, age 45 or age 60, and the full by-age index.

A heart rate zone calculator turns your age into five training bands: 50 to 60 percent of maximum through 90 to 100 percent. Enter a resting heart rate and it also computes Karvonen zones from heart rate reserve, which sit higher, and prints the intensity classification ACSM actually published beside the five zone convention.

Five-zone heart-rate bands (50-60-70-80-90-100% of HRmax)convention — Z1 50-60%, Z2 60-70%, Z3 70-80%, Z4 80-90%, Z5 90-100% of HRmax. Verified 2026-07-30 against ACSM position stand on prescribing exercise intensity as a percentage of maximum heart rate (Garber et al. 2011) (The ten-point band edges are a training-industry convention, not a published finding. No paper derives 50/60/70/80/90/100, and platforms disagree: some anchor zones to heart-rate reserve instead of maximum heart rate, some to lactate or threshold heart rate. Two watches can put the same run in different zones and both be following a defensible chart.)
ACSM relative intensity classification (% of maximum heart rate) — very light <57%, light 57-63%, moderate 64-76%, vigorous 77-95%, near-maximal to maximal >=96% of HRmax. Verified 2026-07-30 against Garber et al., ACSM Position Stand, Med Sci Sports Exerc 2011 (A classification of intensity, not a prescription for an individual, and it sits on top of whatever HRmax estimate you used - so it carries the same 7-11 bpm prediction error underneath.)
Target heart rate (Karvonen, heart-rate reserve) — THR (bpm) = (HRmax - HRrest) x intensity + HRrest. Verified 2026-07-30 against Karvonen, Kentala & Mustala 1957 (Inherits every bit of uncertainty in the HRmax estimate it is built on, plus the accuracy of the resting rate you measured. A resting heart rate taken after coffee or on waking from a bad night can move the answer by several beats.)
Maximum heart rate (Tanaka, 208 - 0.7 x age) — HRmax (bpm) = 208 - 0.7 x age. Verified 2026-07-30 against Tanaka, Monahan & Seals, J Am Coll Cardiol 2001 (Derived by meta-analysis of 351 studies (492 groups, 18,712 subjects, r = -0.90 with age) and cross-validated in 514 more; sex and physical activity level did not shift the regression line. It remains a population regression: individual maximum heart rates at any given age scatter around it, and prediction error for age-based equations is reported at 7-11 bpm. This site therefore renders every predicted HRmax inside a +/-10 bpm band.)
Maximum heart rate (Fox, 220 - age)convention — HRmax (bpm) = 220 - age. Verified 2026-07-30 against Fox, Naughton & Haskell 1971, as documented by Robergs & Landwehr, JEPonline 2002 (There is no published regression behind this equation. Robergs and Landwehr traced it to a line drawn by observation through raw and mean data compiled from roughly eleven sources in 1971, and report a standard error of estimate of 7-11 bpm across two decades of HRmax prediction research. It also underestimates maximum heart rate in older adults, which is the finding Tanaka 2001 was written to report.)
Maximum heart rate in women (Gulati, 206 - 0.88 x age) — HRmax (bpm) = 206 - 0.88 x age. Verified 2026-07-30 against Gulati et al., Circulation 2010 (St James Women Take Heart Project) (Derived in 5,437 asymptomatic women (mean age 52 +/- 11) followed for a mean of 15.9 years, with a reported standard error of about 9 bpm. The paper's central finding for this purpose is that the male-derived equations overestimate peak heart rate for women of the same age.)

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Frequently asked questions

What is my zone 2 heart rate?

On the five-zone convention, zone 2 runs from 60 to 70 percent of your maximum heart rate. At age 50 using Tanaka, that is roughly 104 to 121 bpm. Using Fox instead moves it to 102 to 119, and adding a resting rate of 60 through Karvonen moves it again, to 128 to 151.

Are the five heart rate zones an official standard?

No. The ten-point bands from 50 to 100 percent are a training-industry convention with no paper behind those particular edges. ACSM does publish an intensity classification, and it uses different boundaries: light 57 to 63 percent, moderate 64 to 76, vigorous 77 to 95. This page prints both tables.

Why do my watch and this calculator disagree?

Almost always because they anchor to different things. Some devices scale a percentage of maximum heart rate, some scale heart-rate reserve through Karvonen, some anchor to a measured lactate or threshold heart rate. All three are defensible and all three give different zone edges from the same run.

Should I use Karvonen zones or percent of maximum?

They answer slightly different questions, and this tool shows both rather than choosing. Karvonen scales the span between your resting and maximum rates, so it accounts for a low resting rate; percent of maximum ignores it. Karvonen zones always sit higher at the same nominal percentage.

Is there a fat burning zone?

The proportion of energy coming from fat is highest at lower intensities, and the total energy used is higher at higher ones. That is arithmetic, not a training plan, and this calculator does not label any band as a fat burning zone because the label promises more than the physiology does.

How precise are the zone boundaries?

Not very. The maximum heart rate they are built on carries roughly 7 to 11 bpm of prediction error, so a zone edge computed to the beat is false precision. Treat each band as a broad region, and the numbers this page shows as the middle of a range.

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The next number

No body metric means much on its own. Here is what this one feeds into.

Max heart rate calculatorEvery zone edge here is a percentage of one estimated number. Worth seeing how far apart the three published estimates of it are.TDEE calculatorZones describe intensity; TDEE describes the day the training sits inside.

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Every formula on this page is listed with its source on the methodology page, and changes to any reference value are logged in the data changelog. Canonical URL: https://myhealthmywellness.com/heart-rate-zone-calculator