Heart Rate Training Zone Calculator (Karvonen Formula)

Find your personalized heart rate training zones using the Karvonen (heart rate reserve) formula. Enter your age and resting heart rate to get target bpm ranges for 5 training intensities.

Mathematical Audit

Karvonen Formula (Heart Rate Reserve)

The Karvonen formula calculates target heart rates using your heart rate reserve (HRR) — the difference between your maximum and resting heart rates — rather than a simple percentage of your maximum heart rate alone. Because it factors in your resting heart rate, it adjusts to your individual fitness level and produces more personalized training zones.

Maximum Heart Rate (MHR) = 220 − Age
Heart Rate Reserve (HRR) = MHR − Resting Heart Rate
Target Heart Rate = (HRR × Intensity %) + Resting Heart Rate

The 220 − age formula is a population average estimate of maximum heart rate and can vary by 10-15 beats per minute for any individual. For the most accurate results, use a measured maximum heart rate from a supervised exercise test if available. Always consult a healthcare provider before starting a new exercise program, especially if you take medications that affect heart rate.

Operational Guide

How to Use the Heart Rate Zone Calculator

1

Enter your age

Your age is used to estimate your maximum heart rate using the 220 − age formula.

2

Enter your resting heart rate

Measure your pulse for 60 seconds first thing in the morning, before getting out of bed, for the most accurate resting heart rate.

3

Click Calculate

See your maximum heart rate, heart rate reserve, and target bpm ranges for all 5 training zones.

4

Match zones to your workout

Use Zone 1-2 for recovery and base endurance, Zone 3 for aerobic fitness, and Zones 4-5 for high-intensity interval training.

Real-World Scenario Example

"A 30-year-old with a resting heart rate of 60 bpm wants to find their training zones."

Inputs

age:30
restingHeartRate:60

Result

Maximum heart rate ≈ 190 bpm and heart rate reserve ≈ 130 bpm. Zone 2 (Fat Burn, 60-70% HRR) is about 138-151 bpm, and Zone 4 (Anaerobic, 80-90% HRR) is about 164-177 bpm.

Important Disclaimer

This calculator provides general estimates for informational purposes only and is not a substitute for professional medical advice. Maximum heart rate estimates based on age can vary significantly between individuals. Consult a healthcare provider before beginning a new exercise program, particularly if you have a heart condition or take medications that affect heart rate.