Target Heart Rate Zones Calculator

A target heart rate zone is the range of heartbeats per minute you aim for while exercising. The American Heart Association gives it as 50 to 85 percent of your maximum heart rate^[1].

Inside that range, moderate effort is about 50 to 70 percent and vigorous effort is about 70 to 85 percent. The AHA calls its chart figures averages and says to use them as a general guide^[1].

If you are just starting out, the AHA suggests aiming for the low end, 50 percent, and building up gradually^[1]. In time you may be able to work at up to 85 percent.

There are two steps. First get a maximum heart rate. Then take a percent of it.

Zones are worked out from the rounded maximum and rounded to the nearest beat, halves up. That is how the AHA chart rounds, for example 92.5 becomes 93, so you can check any row by hand.

The five zones

The five-zone table uses the same maximum with edges at 50, 60, 70, 80 and 90 percent. At 180 that gives 90 to 108, 108 to 126, 126 to 144, 144 to 162, 162 to 180. Cleveland Clinic prints the same numbers for a 40-year-old^[4].

Heart rate reserve (Karvonen)

Heart rate reserve is maximum minus resting. The Karvonen method adds a percent of that gap to your resting rate.

This is the formula ACSM prints^[19]. It is named after Karvonen and colleagues, who studied how training changes heart rate in 1957^[16]. I could not read that paper online, so I do not claim what is in it.

The reserve numbers sit higher. The AHA writes its percentages for maximum heart rate^[1], so the calculator shows reserve as a second table and never swaps one for the other.

Every zone depends on the maximum you start from. Six published equations give different answers for the same person. At age 40 they run from 171 to 185, which is 14 beats apart.

I confirmed the Inbar slope from its abstract. I could only confirm the 205.8 intercept through Robergs and Landwehr^[13], who list the sample as men and women. The abstract says men.

No equation wins. A 2020 study compared nine equations with 99 graded treadmill tests. All of them had wide limits of agreement, and Gulati and HUNT differed significantly from measured maximum. The authors said 220 minus age may be the best option for a general population and that a measured maximum is better^[14].

Other sources lean the other way. ACSM's guidelines, as quoted in an ACSM journal article, say 220 minus age can underestimate or overestimate measured maximum and "is no longer recommended"^[19].

The HUNT team says it can miss by up to 40 beats in older people^[15]. Mayo Clinic's own worked example uses Tanaka^[5].

I kept 220 minus age as the default because the AHA chart uses it^[1], so you can check this tool against that chart. Switch the equation to see how far your zone moves. Tanaka, for example, gives 159 at age 70 against 150.

Mayo says your own maximum can differ from an estimate by as much as 15 to 20 beats^[5]. Robergs and Landwehr add that maximum heart rate depends on the exercise mode, and their table lists separate treadmill and bike equations^[13]. This tool does not adjust for mode.

Both tables use 220 minus age, the equation on the AHA chart. The first is the AHA layout, which I extended from ages 20 to 70 up to 80. Rows come from the same function as the calculator.

The five-zone version, by age:

A chart cannot know your resting rate, your fitness or your medicines. Use it to sanity-check the calculator, not to replace it.

The same maximum gives different bands depending on whose guidance you use. The first table is percent of maximum at age 40, with a maximum of 180.

Mayo Clinic repeats the AHA bands, 50 to about 70 percent for moderate and 70 to about 85 for vigorous^[5]. Cleveland Clinic says 60 to 85 percent is typical for people who exercise regularly^[3].

ACSM sorts effort into classes and gives both percent of maximum and percent of heart rate reserve, with ratings of perceived exertion^[2]. The table uses a resting rate of 60.

The classes have gaps because ACSM prints whole percentages, so 76 is moderate and 77 is vigorous. The two methods give different beats for the same class, which fits ACSM's note that the two methods are not necessarily equivalent^[19].

The current CDC page skips percentages and uses perceived effort. On a 0 to 10 scale it calls moderate 5 or 6 and vigorous 7 or 8^[7].

Many calculators split the range into five zones of 10 percent each. Cleveland Clinic lists them as 50 to 60, 60 to 70, 70 to 80, 80 to 90 and 90 to 100 percent of maximum^[4].

I found no study that tests those cut points as physiological boundaries. The tables here give the numbers and no zone names, since names vary from site to site.

If you train by power on a bike, the Cycling Power Training Zones tool works in watts instead.

A resting heart rate of 60 to 100 beats per minute is normal for most adults, according to the AHA. It says an athlete or more active person may be as low as 40^[1].

Resting rate is not a zone. Cleveland Clinic's table lists 60 to 100 for ages 13 to 17 and the same 60 to 100 for ages 18 and above^[3].

The AHA suggests checking it in the morning after a good night's sleep, before you get out of bed^[1].

Resting rate matters only for the reserve method. At a maximum of 180, a 70 percent target is 141 beats with a resting rate of 50 and 147 with a resting rate of 70. If you want your resting rate turned into a fitness estimate, try the Fitness Age Calculator.

Sex: the Tanaka study found no difference between men and women in how maximum heart rate falls with age^[8]. The HUNT study found no interaction with gender and only minor age-adjusted differences^[10]. Gulati built an equation on women and reported that the male-based formula overestimates their maximum^[11], so the sources disagree.

In the 99-person treadmill comparison, Gulati differed significantly from measured maximum^[14]. The calculator does not adjust for sex by default. It lists Gulati and Inbar as options and says who they were built on.

Age: the equations were built on adults, and the HUNT sample ran from 19 to 89^[15]. The calculator warns under 18 and above 89, and blocks ages below 10 and above 100.

Children: Robergs and Landwehr say these equations should not be used for people aged 10 or younger^[13]. The ACSM journal article says no satisfactory equation exists for children and adolescents^[19]. Treat any teen result as a rough guide.

Mayo Clinic describes it this way. At moderate intensity you can talk but not sing. At vigorous intensity you cannot say more than a few words without pausing for breath^[5].

The talk test has published support. One study looked at how consistent it is for exercise prescription^[17]. A later review calls it a useful tool for prescribing and monitoring intensity^[18].

It does not depend on an estimated maximum. Mayo suggests it, with a perceived exertion scale, for people on beta blockers^[6].

For a rating scale, see the RPE Calculator, which covers the Borg 6 to 20 and 0 to 10 cardio scales.

Fat burning has its own page. For that range, use the Fat Burning Zone Calculator. A target zone is a cardio intensity guide, not a fat burning claim.

There are no inputs for gender, fitness level or training goal. In the calculator I replaced they changed little or nothing in the numbers, and I found no sourced rule for how they should.

There is no fuel-source column, no recommended minutes per zone and no zone names. I found no source for them.

Some calculators also label reserve-based numbers as percent of maximum. Here each table says which one it is.

I could not verify the Inbar intercept from a primary source, Karvonen from the original paper, or the age range of the Gulati sample. Those limits are flagged where they come up.