Heart Rate Zone Calculator
Enter your age and resting heart rate (or your known maximum heart rate) and this calculator works out your five Karvonen heart rate training zones — from easy recovery to maximum effort — so you know what to aim for on your next workout.
How it works
This calculator uses the Karvonen formula, which factors in your resting heart rate as well as your maximum: target HR = ((max HR − resting HR) × intensity) + resting HR. Your maximum heart rate is estimated as 220 minus your age unless you enter a known value, and each zone uses a different intensity range of your heart rate reserve.
Tip
If you've had your max heart rate measured directly (in a lab or supervised fitness test), enter it for more accurate zones — the age-based estimate (220 − age) is a population average and can be off by 10-20 beats per minute for any individual.
Is this medical advice?
No — this is a general fitness estimate based on standard formulas, not personalized medical or training advice. If you're new to exercise, pregnant, or have a heart condition or other health concerns, talk to a doctor before starting an intense exercise program.
More tools in this category
One-Rep-Max Calculator
Estimate your one-rep max (1RM) from any weight and rep count, with a training percentage table.
Running Pace Calculator
Calculate your running pace and speed from distance and time, with predicted race finish times.
Swim Pace Calculator
Calculate your swimming pace per 100 meters or yards from distance and time, with predicted times for common distances.
VO2 Max Calculator
Estimate your VO2 max from your age and resting heart rate, no exercise test required.