Target Heart Rate Calculator

Karvonen zones using your resting heart rate.

Calculate target heart rate ranges with the Karvonen heart-rate-reserve method, which uses resting heart rate for a more personal result.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Age

years

Resting heart rate

bpm

Measured on waking, before getting out of bed, averaged over several mornings.

Target intensity70 %

Target heart rate

146 bpm

70% of heart rate reserve

Estimated max (Tanaka)184 bpm

Heart rate reserve124 bpm

Easy end (60%)134 bpm

Hard end (85%)165 bpm

Karvonen works from the gap between resting and maximum, so a fitter heart with a lower resting rate gets appropriately different targets.

How the Target Heart Rate Calculator works

Percentage-of-maximum zones ignore how fit you already are. The Karvonen method works from heart rate reserve, the gap between resting and maximum, so a well-trained person with a resting pulse of 45 gets different targets from someone at 75, as they should.

Also known as: training heart rate zone · Karvonen formula calculator · heart rate for fat burning · target heart rate calculator · target heart rate formula

Two ways to set a target

The simple method takes a percentage of maximum heart rate. Sixty per cent of a 185 maximum is 111 beats per minute.

The Karvonen method uses heart rate reserve, which is maximum minus resting. The target is resting plus a percentage of that reserve. With a maximum of 185 and a resting rate of 55, the reserve is 130, and 60% gives 55 plus 78, which is 133.

The two produce noticeably different numbers, and Karvonen is generally preferred because it accounts for the individual's resting rate. A fit person with a low resting heart rate gets a higher target from Karvonen, which better reflects the effort involved.

Measuring resting heart rate properly

Resting heart rate should be measured on waking, before getting out of bed, ideally averaged over several consecutive mornings.

A reading taken after coffee, after standing, or during the day is not a resting rate. The difference can easily be 10 to 15 beats, which shifts every Karvonen target meaningfully.

Tracking it over time is worthwhile independently. A resting rate that has risen five or more beats above its usual level frequently indicates incomplete recovery, illness coming on, or accumulated fatigue, and it is one of the more useful signals available without any equipment.

The zones and what each does

Very light effort, roughly 50% to 60% of reserve, supports recovery and general activity. Light, 60% to 70%, builds aerobic base and is where most endurance training volume should sit.

Moderate, 70% to 80%, improves aerobic capacity and is the zone most people default to and overuse. Hard, 80% to 90%, develops the ability to sustain effort near threshold. Maximal, above 90%, develops peak capacity and can only be sustained briefly.

The common error is training almost everything in the moderate zone: too hard to accumulate volume without fatigue, too easy to drive high-intensity adaptation. Polarised training, which puts most volume in the easy zone and a small proportion very hard, has reasonable evidence behind it in endurance athletes.

What shifts heart rate besides effort

Cardiac drift raises heart rate over a prolonged session at constant effort, driven by dehydration and rising core temperature. An hour into a steady run, heart rate can be 5% to 10% higher for the same pace.

Heat, altitude, caffeine, illness, poor sleep and stress all raise it. Some medications, particularly beta blockers, lower it substantially and make percentage-of-maximum targets meaningless.

Which means heart rate is a measure of physiological strain rather than of external workload. On a hot day at the same pace, the heart rate is higher because the strain genuinely is higher, and slowing down to hold the target is usually the correct response rather than a failure.

When to ignore the number

Rate of perceived exertion correlates well with heart rate and is free, always available and unaffected by the factors above. For most people training for health it is entirely sufficient.

The talk test is the simplest version and is genuinely useful: able to hold a conversation is easy effort, able to speak in short sentences is moderate, unable to speak is hard.

Heart rate monitoring earns its place in structured endurance training, where controlling intensity precisely across long sessions matters. For general fitness it adds precision that the underlying prescription does not require.

Where to go next

The Target Heart Rate question rarely arrives on its own. These are the ones that usually come with it:

Max Heart Rate Calculator — Four formulas, because 220 minus age is the worst of them.
Heart Rate Zone Calculator — All five training zones, with what each is for.
VO2 Max Calculator — Aerobic capacity estimated from resting heart rate or a race time.
BMI Calculator — Body mass index with category and healthy weight range.

Sources

ACSM, Guidelines for Exercise Testing and Prescription

Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.

Frequently asked questions

What is the Karvonen formula?

Target = ((max HR − resting HR) × intensity) + resting HR. The bracket is your heart rate reserve. At 70% intensity with a max of 190 and a resting rate of 60, the target is ((190 − 60) × 0.7) + 60 = 151 bpm.

How do I measure resting heart rate properly?

Immediately on waking, before getting out of bed, for several consecutive mornings, then average them. Anything measured after coffee, movement or stress reads high. A wearable that samples overnight generally does this better than a manual count.

Is the fat burning zone real?

It is real but widely misunderstood. At low intensity a higher proportion of energy comes from fat, yet the total energy burned is small. Harder work burns more fat in absolute terms per session. Zone choice should follow your training goal, not a label on a treadmill.

Karvonen or percentage of max heart rate?

Karvonen, if you know your resting heart rate reasonably accurately. It accounts for individual fitness and generally gives targets closer to lab-measured thresholds. Plain percentage-of-max is fine when you have no reliable resting figure.