Target Heart Rate Calculator

This works out the heart rate range to aim for during exercise. Enter your age, or a maximum measured in a test, and it returns the five training zones. Add a resting heart rate and it switches to the Karvonen method, which is more personal than a plain percentage of maximum. You can also read the zones against either of the two perceived exertion scales.

What heart rate is

Heart rate is the number of contractions your heart makes per minute, measured in beats per minute. Using this calculator well means understanding three related figures: resting heart rate, maximum heart rate, and the reserve between them.

Maximum heart rate

Maximum heart rate is the highest rate your heart reaches during intense exercise. It is measured most accurately in a cardiac stress test, where exercise intensity is raised in stages, usually on a treadmill or bike, while heart function is monitored.

Most people estimate it from a formula instead, and those formulas have been criticised, fairly, for producing population averages rather than individual values. The calculator offers three:

Haskell & Fox (1971): MHR = 220 − age

Tanaka, Monahan & Seals (2001): MHR = 208 − 0.7 × age

Nes, Janszky, Wisloff, Stoylen & Karlsen (2013): MHR = 211 − 0.64 × age

The famous one is also the weakest. 220 − age was not the product of original research; it came from a 1971 review that fitted a rough line through around eleven existing datasets, and it stuck because it is easy to remember. Tanaka's 2001 meta-analysis drew on 351 studies covering more than 18,000 people, and Nes's 2013 equation came from the Norwegian HUNT Fitness Study, which measured maximum heart rate directly in around 3,300 healthy adults.

The chart above shows how far apart they drift. At 30 they sit within 5 bpm of each other, but by 60 the gap reaches 13. Below about 25, 220 − age reads highest; above about 40 it reads lowest, and it understates maximum heart rate for most older adults.

The more important caveat applies to all three. Individual maximum heart rates scatter around any age-based estimate with a standard deviation of roughly 10 to 12 bpm. For a 30-year-old, a predicted 190 means a true maximum plausibly anywhere from about 170 to 210. If your zones consistently feel wrong, trust that feeling over the formula.

Resting heart rate

Resting heart rate is your rate at rest: awake, in a comfortable room, not stressed or startled. Measure it first thing in the morning before getting up, over several days, and take the average.

A typical adult figure is 50 to 90 bpm. You will still see 60 to 100 quoted, but that range is dated. Above the upper bound is tachycardia; below the lower bound is bradycardia. Both can indicate a problem, though a low resting rate in a trained endurance athlete is normal and often a sign of an efficient heart, resting rates in the 40s are unremarkable in that group.

Resting heart rate is also the single most useful daily number a recreational athlete can track. A rise of 5 to 10 bpm above your own baseline often shows up before you consciously feel under-recovered, dehydrated, or ill.

Heart rate reserve

Heart rate reserve is the working range between rest and maximum:

HR reserve = MHR − RHR

Someone with a maximum of 180 and a resting rate of 68 has a reserve of 112 bpm. That is the span your training zones are carved out of.

The five training zones

Intensity is usually divided into five zones, each with its own purpose:

Zone 1 (50–60%): light to moderate. Warm-ups, cool-downs, recovery days and easy sessions live here.

Zone 2 (60–70%): endurance and fat metabolism. It takes real effort but can be sustained for a long time, and it forms the bulk of most well-built endurance programmes.

Zone 3 (70–80%): harder to hold, and where speed and strength develop.

Zone 4 (80–90%): close to maximum effort. This trains how long you can hold a high output.

Zone 5 (90–100%): maximum effort, sustainable only briefly. It improves muscular efficiency and cardiovascular fitness, but should be a small fraction of total training.

Each zone does something different, so a programme should be built across them rather than parked in one. The common mistake is spending most sessions in zone 3. It is too hard to recover from, too easy to drive adaptation. Trained endurance athletes typically do the large majority of their volume in zones 1 and 2.

Percent of maximum, and the Karvonen method

There is no single agreed way to measure intensity, which is why the calculator offers several.

The straightforward approach uses maximum heart rate alone, and it is what the calculator falls back on when no resting rate is given. Take a 36-year-old: 220 − 36 gives an MHR of 184. For a moderate 70–80% zone, multiply:

184 × 0.70 = 129   and   184 × 0.80 = 147

So a moderate zone of 129 to 147 bpm.

The Karvonen method uses heart rate reserve instead, which folds in resting heart rate and is the default here once you supply one. Multiply the percentage by the reserve, then add resting heart rate back:

THR = RHR + (MHR − RHR) × intensity

For the same person with a resting rate of 70, the reserve is 184 − 70 = 114:

0.70 × 114 + 70 = 150   and   0.80 × 114 + 70 = 161

That gives a moderate zone of 150 to 161 bpm, noticeably higher than the 129 to 147 the simpler method gave. That difference is the point. A fit person with a low resting rate gets zones that reflect their actual working range rather than being handed targets that are too easy.

Rating of perceived exertion

Perceived exertion lets you rate intensity subjectively, without measuring anything. That is useful when you have no monitor, and genuinely important for anyone whose heart rate is unreliable as a guide, beta blockers and some other medications blunt the heart rate response entirely, and so do certain arrhythmias. In those cases RPE is the better instrument, and heart rate zones may be meaningless.

Two scales are in common use.

The Borg scale is the original, running from 6 to 20, where 6 is no exertion and 20 is maximal. The odd range is deliberate: multiply a rating by ten and you land near the heart rate of a healthy young adult at that effort. Target heart rate follows from:

THR = RHR + (MHR − RHR) × (B − 6) ÷ 14

For a "somewhat hard" effort at 13, with a maximum of 190 and a resting rate of 60:

60 + (190 − 60) × (13 − 6) ÷ 14 = 125 bpm

The Borg CR10 scale is the modified version, running 0 to 10, where 0 is nothing at all and 10 is the strongest exertion you have experienced. It maps proportionally:

THR = RHR + (MHR − RHR) × B ÷ 10

At a "somewhat difficult" 4, the same person gets 60 + 130 × 0.4 = 112 bpm.

A simpler field test works alongside either scale. If you can hold a conversation but not sing, you are around moderate intensity. If you can only manage a few words at a time, you are in the vigorous range. It costs nothing and needs no equipment.

Finding your real maximum

If the formulas bother you, measure instead. The gold standard is a supervised graded exercise test, which raises intensity in stages until you cannot continue. Clinics, sports labs and many universities run them.

A field test gets you closer than an equation without the lab. After a thorough warm-up, run or ride hard for three minutes, recover easily for three, then repeat the effort harder than the first. The highest reading across the second effort is close to your true maximum. It is genuinely unpleasant, and it is not something to attempt if you are new to exercise, unwell, or have any cardiac history. Do it with medical clearance or not at all. Enter the number in the "Test result" field and every zone recalculates around it.

One misconception worth clearing up: maximum heart rate barely responds to training. Get fitter and your VO₂ max improves, your threshold moves up, your resting rate falls and your reserve widens, but your maximum stays roughly where it is and drifts down slowly with age. A falling maximum is not a sign of lost fitness, and chasing a higher one is chasing the wrong number.

Two numbers worth tracking alongside

Threshold heart rate. Roughly the highest rate you could hold for an hour, sitting near the top of zone 4. It responds strongly to training and is a better progress marker than maximum heart rate, because it moves when you improve. Many training plans set zones from threshold rather than maximum for exactly that reason.

Recovery heart rate. How far your rate falls in the first minute after stopping a hard effort. A drop of more than about 20 bpm is typical for a reasonably fit person, and the figure improves as aerobic fitness does. A consistently slow recovery is worth mentioning to a doctor.

Things that shift your numbers

Cardiac drift. Hold a steady pace for an hour and your heart rate climbs anyway, often 5 to 10 bpm, as fluid is lost and core temperature rises. Late in a long session a given heart rate represents less work than it did at the start.

Heat, altitude and dehydration all raise heart rate at the same workload. Zones set in cool conditions will feel wrong on a hot day.

Caffeine, illness and poor sleep move it too, which is why a single day's reading means less than a trend.

Your monitor. Wrist optical sensors work reasonably well at steady effort but lag during intervals and can lock onto cadence instead of pulse. A chest strap is markedly more accurate for interval work.

Reading the result

The headline range is the 50 to 85% band commonly recommended for aerobic exercise, and the table breaks the whole range into zones. Public health guidance from the American Heart Association and ACSM asks for 150 minutes of moderate activity a week, or 75 minutes of vigorous, and the moderate and hard rows show what those intensities mean for you in beats per minute.

Treat all of it as a starting point. An age-based maximum is a population average, so calibrate against how sessions actually feel and adjust. If you take medication that affects heart rate, or have a heart condition, speak to a doctor before setting training intensities from any calculator. Our Pace Calculator and Calories Burned Calculator cover the other side of the same session.