What is the Karvonen method?

The Karvonen method estimates target heart rate by applying a chosen intensity percentage to heart rate reserve (the difference between maximum and resting heart rate), then adding resting heart rate back. It was introduced by Martti Karvonen in 1957 and remains widely used in exercise prescription.

How does the Karvonen formula differ from percentage of max heart rate?

Simple percentage-of-max formulas multiply estimated maximum heart rate by an intensity percentage. The Karvonen method first subtracts resting heart rate, applies the intensity percentage to that reserve, then adds resting heart rate back. This typically yields slightly higher target zones for a given percentage, especially in individuals with lower resting heart rates.

How is resting heart rate best measured?

Resting heart rate is typically measured immediately upon waking, while still lying down, before caffeine or food intake. Consistent measurement conditions—same time of day, hydration status, and body position—reduce day-to-day variability. Multi-day averages provide more stable input values than single readings.

Why does the tool use 220 minus age for maximum heart rate?

The 220-minus-age formula is a widely published population estimate. It carries a standard deviation of approximately ±10–12 bpm, meaning roughly one-third of individuals fall outside ±10 bpm of the prediction. Laboratory testing (graded exercise test to volitional exhaustion) provides a more precise individual maximum.

What do Light, Moderate, and Vigorous intensity levels correspond to?

The intensity labels map to commonly used heart rate reserve percentage ranges: Light typically corresponds to 50–63% of reserve, Moderate to 64–76%, and Vigorous to 77–95%. These ranges align broadly with established guidelines from organizations such as the American College of Sports Medicine.

Heart Rate Zones

Heart Rate Zones (Karvonen Method)

Calculate target heart rate zones using the Karvonen heart rate reserve method.

Last updated: 22 April 2026

What this tool does

This calculator computes target heart rate zones using the Karvonen formula, which applies heart rate reserve—the difference between maximum and resting heart rate—to scale exercise intensity. It requires age, resting heart rate in beats per minute, and a desired intensity percentage, then outputs a target heart rate for that intensity level. Published by Martti Karvonen in 1957, this method accounts for individual resting heart rate variability and is widely used in aerobic training prescription.

Inputs

Result

—

Formula Used

Z = (MHR - RHR) \times i + RHR

a

Age in years

RHR

Resting heart rate in bpm

i

Target intensity (decimal)

Spotted something off? Let us know — we update calculators regularly.

How Heart Rate Zones (Karvonen Method) works

This calculator applies the Karvonen formula to estimate a target heart rate at a chosen intensity level. It accounts for both maximum heart rate (estimated as 220 minus age) and resting heart rate, then applies a percentage of the heart rate reserve to determine the working zone. The tool accepts age, resting heart rate, and an intensity level (Light, Moderate, or Vigorous), then returns the corresponding target heart rate in beats per minute.

The formula

The Karvonen method calculates target heart rate as:

Target HR = ((MHR − RHR) × Intensity%) + RHR

where MHR is maximum heart rate (220 − age), RHR is resting heart rate, and Intensity% represents the selected training zone. This approach incorporates heart rate reserve—the difference between maximum and resting rates—to scale intensity more precisely than simple percentage-of-maximum formulas.

Where this method is most accurate

The Karvonen formula assumes a linear relationship between heart rate reserve and oxygen consumption. It relies on the 220-minus-age equation for maximum heart rate, which carries a standard deviation of approximately ±10–12 bpm in adult populations. Resting heart rate measurement accuracy depends on consistent timing (typically upon waking, before rising) and environmental conditions. Individual variation in autonomic tone, cardiovascular fitness, medication use, and genetic factors can shift both maximum and resting values outside population norms.

What this tool does not do

This calculator generates mathematical estimates from published formulas; it does not measure actual heart rate, assess cardiovascular health, or provide training prescriptions. It does not replace heart rate monitor data, medical evaluation, or sport-specific testing protocols such as lactate threshold or VO₂max assessments. The tool does not account for altitude, heat acclimatization, dehydration, illness, or medication effects that alter heart rate response to exercise.

Disclaimer

This tool is for educational and informational purposes only. It is not medical advice, a diagnostic instrument, or a substitute for consultation with a qualified healthcare or exercise professional. All outputs are population-based estimates; individual physiology varies. Users bear sole responsibility for how they apply these numbers.

Questions

What is the Karvonen method?: The Karvonen method estimates target heart rate by applying a chosen intensity percentage to heart rate reserve (the difference between maximum and resting heart rate), then adding resting heart rate back. It was introduced by Martti Karvonen in 1957 and remains widely used in exercise prescription.
How does the Karvonen formula differ from percentage of max heart rate?: Simple percentage-of-max formulas multiply estimated maximum heart rate by an intensity percentage. The Karvonen method first subtracts resting heart rate, applies the intensity percentage to that reserve, then adds resting heart rate back. This typically yields slightly higher target zones for a given percentage, especially in individuals with lower resting heart rates.
How is resting heart rate best measured?: Resting heart rate is typically measured immediately upon waking, while still lying down, before caffeine or food intake. Consistent measurement conditions—same time of day, hydration status, and body position—reduce day-to-day variability. Multi-day averages provide more stable input values than single readings.
Why does the tool use 220 minus age for maximum heart rate?: The 220-minus-age formula is a widely published population estimate. It carries a standard deviation of approximately ±10–12 bpm, meaning roughly one-third of individuals fall outside ±10 bpm of the prediction. Laboratory testing (graded exercise test to volitional exhaustion) provides a more precise individual maximum.
What do Light, Moderate, and Vigorous intensity levels correspond to?: The intensity labels map to commonly used heart rate reserve percentage ranges: Light typically corresponds to 50–63% of reserve, Moderate to 64–76%, and Vigorous to 77–95%. These ranges align broadly with established guidelines from organizations such as the American College of Sports Medicine.

Sources & Methodology

The Karvonen formula calculates target heart rate as ((MHR − RHR) × Intensity%) + RHR, where MHR = 220 − age. Published by Martti Karvonen in 1957, it scales exercise intensity using heart rate reserve rather than simple percentage of maximum heart rate.

More in Heart Rate Zones

View all 6 →