Target Heart Rate Calculator

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Simple percentage vs. the Karvonen method

Without a resting heart rate, zones are estimated as a straight percentage of your max heart rate (220 − age). With a resting heart rate entered, the calculator switches to the Karvonen method, which factors in your heart rate reserve (max minus resting) — generally considered more personalized, since two people with the same max heart rate can have very different fitness levels reflected in their resting heart rate.

Frequently asked questions

Is "220 minus age" an exact formula? No — it's a widely used population-average estimate for maximum heart rate, but individual max heart rate can vary by 10–20 beats per minute from this estimate. A supervised max-effort fitness test gives a more precise number if you need one.

What are these zones used for? The "fat burn" zone is a lower-intensity, sustainable pace often used for base endurance; the "cardio" zone builds cardiovascular fitness; and the "peak" zone is high-intensity effort typically sustained only briefly, such as in interval training.

Why does resting heart rate change my zones? A lower resting heart rate (often a sign of better cardiovascular fitness) widens your heart rate reserve, which the Karvonen method uses to calculate proportionally higher target zone numbers compared to the simple percentage method.