Heart Rate Zone Calculator (Karvonen Method)
Calculate your 5 heart rate training zones using the Karvonen method. Free HR zone calculator for smarter cardio and fat-burning workouts.
How this calculator works
The Karvonen method uses your resting heart rate as well as your age, which makes the zones more personal than a simple 220-minus-age estimate.
Measure resting heart rate before you get out of bed, on three separate mornings, and use the average. Most of your cardio should sit in zone 2 — conversational effort — with a small amount of hard work above it.
Frequently asked questions
What is the fat burning zone?
Lower intensities use a higher percentage of fat for fuel, but total calories burned and overall consistency matter far more for fat loss.
Why is my watch's zone 2 different?
Watches often use age-based formulas and their own zone model. A calculator using your resting heart rate is usually closer to reality.
How much time should I spend in each zone?
A common split is roughly 80 percent easy zone 2 work and 20 percent hard efforts in zones 4 and 5.
More free calculators
TDEE Calculator (Total Daily Energy Expenditure) · One Rep Max (1RM) Calculator · Body Fat Percentage Calculator (U.S. Navy Method) · Macro Calculator (Protein, Carbs & Fat) · FTP Calculator (Functional Threshold Power) · Wilks Score Calculator · BMI Calculator (Body Mass Index)