Karvonen Formula Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Body measurements become more useful when the formula behind them is easy to see. Karvonen Formula Calculator turns its specific inputs into one focused estimate.

What this calculator does

Training intensity is easier to personalize when resting heart rate is included. The Karvonen method uses heart-rate reserve—the gap between resting and maximum heart rate—to estimate a target exercise heart rate. Anthropometric equations are convenient because they use simple measurements, but they describe body size or proportion rather than directly measuring tissue composition or health.

How to use it

Enter or select Resting heart rate, Do you know the maximum HR?, Maximum heart rate, Age, and Intensity. Use the units offered by the calculator and keep measurements consistent when you plan to compare results over time.

How the calculation works

Target heart rate = resting heart rate + intensity fraction × (maximum heart rate − resting heart rate). If maximum heart rate is not entered, the calculator estimates it with 220 − age before applying the Karvonen formula.

Example

For the sample values prefilled in this calculator, the primary result is 151 bpm (Target heart rate), Maximum heart rate is 190 bpm, and Heart-rate reserve is 130 bpm. This example is there to show how the inputs flow through the implemented equation; replace the sample values with your own measurements before using the result.

How to interpret the result

The output is a target beats-per-minute value for the chosen intensity. It is a planning guide for steady exercise effort, not a guarantee that the same heart rate represents the same physiological strain for everyone.

Limitations and notes

Age-predicted maximum heart rate has substantial individual variation, and medications, heat, dehydration, illness, fitness level, and rhythm disorders can alter heart-rate response. People with cardiovascular disease or exercise restrictions should use clinician-provided limits when available. For repeat measurements, consistency usually matters more than false precision: use the same unit system, the same tape or scale when possible, and the same anatomical landmarks. A small change near a category boundary should be viewed in context rather than treated as a sudden biological change.