Choose maximum heart rate or heart rate reserve
A target heart rate zone is a band of beats per minute that you aim to stay inside during exercise. Every band is built from a maximum heart rate, and there are two common ways to turn that maximum into a zone. The simple way takes a percentage of the maximum. A 70% effort for someone with a maximum of 190 beats per minute is 0.70 × 190 = 133. The second way, often called the Karvonen method, starts from your resting heart rate and adds a percentage of the gap between resting and maximum. That gap is the heart rate reserve. With a maximum of 190 and a resting rate of 70, the reserve is 120, and a 70% effort is 70 + 0.70 × 120 = 154 beats per minute.
The two methods give different numbers for the same percentage, because they measure from different starting lines. The calculator never switches between them for you, even if you type a resting rate. You pick the basis with a visible selector, and every table and chart says which one it used. Comparing a zone from this page with a zone from a watch or an app only makes sense when both use the same basis. You can also enter a maximum you already know instead of using an age formula. A value you trust from your own history is likely better than a formula, but the page cannot tell where your number came from.
Three age-based maximum heart rate formulas
If you do not know your maximum, the page estimates it from age with one of three published equations. They differ in how fast they say the maximum falls with age, so the gap between them grows over the years. At age 30 they give 190.0, 187.0 and 191.8 beats per minute, and at age 50 they give 170.0, 173.0 and 179.0. All three are averages over groups of people, and an individual can sit far from them in either direction.
Fox: 220 − age
This is the best-known rule because it is easy to do in your head. It subtracts your age in years from 220. Its history is informal. It spread through exercise guidance for decades, and the original derivation was not retrieved for this page, so no claim is made here about the group it came from. At age 30 it gives 190.
Tanaka: 208 − 0.7 × age
A 2001 analysis combined data from many published studies and a laboratory sample of healthy adults, and arrived at 208 minus 0.7 times age. Its slope is gentler than the Fox rule, so it gives higher estimates for older people (Tanaka et al., 2001). At age 30 it gives 187.0.
Nes: 211 − 0.64 × age
A 2013 study of healthy Norwegian adults who each performed a maximal treadmill test produced 211 minus 0.64 times age (Nes et al., 2013). It sits close to Tanaka with a slightly higher intercept. At age 30 it gives 191.8.
How target heart rate zones are calculated
The calculator shows five adjacent bands, from 50 to 60%, 60 to 70%, 70 to 80%, 80 to 90% and 90 to 100%. For a percentage p, the percent-of-maximum rule gives p × M, where M is the maximum heart rate. The reserve rule gives R + p × (M − R), where R is the resting rate. The bands touch each other, and the number at the top of one is the number at the bottom of the next. They are boundaries on a line, not separate boxes, so a heart rate exactly on the edge belongs to both. Calculations run on unrounded values. The page shows whole beats per minute in the headline and tables, and one decimal in the detail tables and the downloadable file.
You can also set a custom band. Type a lower and an upper percentage from 0 to 100, with the lower below the upper, and the page adds one extra row using the basis you already picked. Clear both boxes to leave it out. The band names are only illustrative labels for ranges of percentage. They are not clinical categories and they are not a prescription. The page deliberately does not tell you which zone burns the most fat or which one is best for your goal, because those claims depend on things a percentage cannot show.
Where the numbers come from matters as much as the formula. A resting heart rate is best taken in the morning after you wake, lying still, before coffee or exercise, and it is more trustworthy as the typical value over several mornings than as a single reading. A measured maximum is a different matter: reaching it means a maximal effort, which is hard to do well and not appropriate for everyone. If you have never measured it, the age-based estimates are a reasonable starting point, and you can replace them later with a value you have good reason to trust. The page lets you enter your own maximum for exactly that case.
Worked age-based and measured-max examples
Take a 30-year-old and the Fox formula, so M = 190. On the percent-of-maximum basis, the 50% end of the first band is 95.0 and the 85% point, the top of the vigorous range the American Heart Association quotes, is 161.5. Now add a resting rate of 70 and switch to the reserve basis. The reserve is 190 − 70 = 120, the 50% point is 130, the 70% point is 154, the 80% point is 166 and the 85% point is 172 beats per minute.
If you have a measured maximum of 180 and a resting rate of 70, the reserve is 110. The 50% point becomes 125.0 and the 85% point is 163.5 beats per minute. In this mode the age and the age formula are ignored, so changing them does nothing. The page rejects a resting rate that is not below the maximum, and it does not read a blank resting rate as zero. A blank resting rate simply blocks the reserve basis, and it is ignored on the percent-of-maximum basis.
The zone edges are conventions, not physiological switches. Your body does not change gear when your heart rate crosses a boundary, so being a few beats above or below the edge of a band does not mean you have left that kind of effort. Many things move your heart rate for the same workload: heat, humidity, dehydration, caffeine, poor sleep, stress, altitude, illness and a fitness change over the season. A reading in the middle of a band on a hot day can feel harder than the same reading on a cool one. That is one more reason to treat the bands as a rough guide and to let how the effort feels, such as whether you can talk in full sentences, inform the number.
Why zone systems and perceived effort differ
Heart rate zones are one way to describe effort, and not every system agrees. Some use five zones and others three or seven. Some anchor to maximum heart rate, some to reserve, and some to a threshold found in a lab or field test. Two systems can both call a zone the second one while meaning different beats per minute. Your watch may also use its own estimate of your maximum, and update it as you train. So when a number on this page differs from a device, first check whether the basis and the maximum match.
Perceived effort is a separate scale. How hard a run feels depends on sleep, heat, hydration, caffeine, illness, the time of day and what you did yesterday, as well as on heart rate. A rating of effort does not map to a heart rate by a fixed formula, so the page does not convert one into the other. If you want to know how a given pace relates to a distance and a time, use the running pace calculator, and for the energy cost of an activity, see the calories burned estimate page.
Heart rate also lags effort. When you start a steady run or an interval, it takes a minute or more to climb, and when you stop it takes time to fall, so a number glanced at in the first minutes does not describe the effort you are making. Over a long session, heart rate can also drift upward at the same pace as you warm up and lose fluid. For these reasons it is more useful to look at the average over several minutes of steady effort than at any single reading, and to compare sessions done in similar conditions.
Medication, measurement and individual limits
An age-based maximum is a population estimate, not a personal ceiling and not a safety limit. Two healthy people of the same age can have maximum heart rates tens of beats apart. Several medicines, notably beta-blockers, lower heart rate response to exercise, and some heart conditions change what is appropriate. If you take medication that affects your heart, or have a heart or lung condition, ask your clinician what range suits you rather than using the numbers here. Resting heart rate also moves with illness, stress and sleep, so a reading taken on a bad week will shift a reserve zone.
Measurement matters as well. Chest straps tend to track beats more closely than wrist sensors during hard intervals, and any sensor can misread. The page does not explain how to test your maximum, because a maximal effort is not appropriate for everyone. If you enter a measured maximum, it should come from a source you trust. Nothing shown here clears you to exercise, and no result is a diagnosis. Chest pain, dizziness or unusual breathlessness are reasons to stop and seek medical advice, whatever a zone table says.
The heart rates shown are rounded to whole beats per minute, and the band edges are shown as ranges. That precision describes the arithmetic, not your body, and a wrist sensor adds its own error on top of the formula. Treat the bands as a planning aid and not as a measurement of anything about your health. If you notice chest pain, dizziness, unusual breathlessness or an irregular heartbeat during exercise, stop and seek medical advice instead of trying to reach a number on a page.
Sources and update policy
The American Heart Association describes moderate-intensity exercise as about 50% to 70% of maximum heart rate and vigorous exercise as about 70% to 85%, as average guidance (AHA target heart rates). The page shows those ranges separately and always on the percent-of-maximum basis. The formulas come from the studies cited above. Sources were checked on 8 November 2026 and are reviewed at least once a year, and again before any change to a formula. For other tools, see the fitness and health calculators.
Target heart rate questions
What is the difference between max and reserve zones?
Max zones multiply a percentage by your maximum heart rate. Reserve zones start from your resting rate and add the percentage of the gap to the maximum, so they use R + p × (M − R). At a maximum of 190 and a resting rate of 70, 70% is 133 on the first basis and 154 on the second.
Which age formula is most accurate?
None is accurate for every person. They are population estimates built on different groups, and individual maximums scatter widely around them. Compare them and treat the result as a starting estimate, not as a personal best.
Can I enter a measured maximum?
Yes. Choose the entered-value option and type a number from 80 to 240 beats per minute. The page uses it directly and ignores your age. It does not recommend that anyone test their own maximum.
Why does my watch show a different zone 2?
Zone definitions vary. A device might use a different maximum, a reserve basis, a threshold-based system or a different percentage range for that zone. Compare like with like before deciding which number to follow.
Can I use these zones while taking medication?
Generic estimates may not apply if a medicine changes your heart rate response. Ask your clinician or pharmacist for personal guidance. This page does not adjust zones for any drug or dose.