By Zencalcy Editorial TeamLast reviewed About us
The Karvonen formula sets a target heart rate from your resting heart rate and a chosen exercise intensity. Unlike a simple percentage of maximum heart rate, it accounts for your fitness baseline, so two people of the same age can get different targets. It is widely used in endurance training.
Set a target heart rate from resting heart rate and intensity.
| Typical aerobic range: 60–80%. | |
Target HR = ((max HR − resting HR) × intensity%) + resting HR Max HR (220 − age) is the default; Tanaka (208 − 0.7 × age) is an alternative.
Karvonen uses heart-rate reserve, the gap between resting and maximum heart rate. A 70% Karvonen intensity is harder than 70% of max HR. If you take a beta-blocker or have a heart condition, target heart rates from formulas may not apply.
| Symbol | Meaning |
|---|---|
| Max HR | Estimated maximum heart rate in beats per minute. |
| Resting HR | Heart rate at rest, ideally measured on waking. |
| Intensity | Exercise intensity as a percentage of heart-rate reserve. |
Max HR = 220 − 35 = 185. Reserve = 185 − 60 = 125. Target = 125 × 0.70 + 60 = 147.5, rounded to 148 bpm. At 85% the target is 166 bpm.
Heart-rate reserve is the difference between your maximum and resting heart rate. A person with a resting rate of 45 has a much larger reserve than a person of the same age with a resting rate of 75, even though both might have the same estimated maximum. Karvonen scales the target to that reserve. This is why a fit endurance athlete often trains at heart rates that look high relative to their age-predicted maximum, while an untrained person reaches the same relative effort at a lower number. The formula still relies on an estimated maximum, which can be off by ten beats or more. A field test or lab test gives a better anchor, but it is not necessary for most recreational training. Use the calculated target as a starting band, then adjust by perceived effort and actual performance.
Continue with the ABSI Calculator (A Body Shape Index), Adjusted Body Weight Calculator, or the BAI Calculator (Body Adiposity Index) — or browse more body measurements tools and all health calculators.
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It is more individual because it uses your resting heart rate. Percent of max ignores fitness, so it can prescribe the same target to a trained and an untrained person of the same age.
Every result is a screening estimate from published anthropometric equations, not a diagnosis or a measurement of body composition. Tape measurements should be taken snugly against the skin without compressing it, at the landmarks named in each tool. Equations were derived in specific populations and can be less accurate for athletes, older adults, children, pregnant people and people with significant oedema.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026