How to use this heart rate calculator
- Age, enter your age in years.
- Resting heart rate (optional), enter your resting beats per minute if you know it. Leave it blank to use maximum heart rate only.
- Read your maximum heart rate and the bpm range for each of the five zones, they update instantly as you type.
Nothing is submitted or stored: the numbers never leave your device, so you can check your figures and plan your training privately.
How target heart rate is calculated
Your maximum heart rate is estimated with the standard formula max HR = 220 - age. So a 40 year old has an estimated maximum of about 180 beats per minute. The five training zones are simply percentages of that maximum: Zone 1 very light is 50 to 60 percent, Zone 2 light is 60 to 70 percent, Zone 3 moderate is 70 to 80 percent, Zone 4 hard is 80 to 90 percent, and Zone 5 maximum is 90 to 100 percent.
If you also enter a resting heart rate, the tool switches to the Karvonen method, which gives more personal zones. It first works out your heart-rate reserve = maximum heart rate - resting heart rate. Each target is then reserve x percent + resting heart rate. Because it folds in how low your resting rate is, the Karvonen method tends to produce slightly different, more individual numbers than using the maximum alone. All results are rounded to whole beats per minute.
Using the zones
Lower zones (1 and 2) suit warm-ups, recovery and long easy efforts. The middle zone (3) is a comfortable aerobic pace often linked with steady endurance work. The top zones (4 and 5) cover hard threshold and interval training that you can only hold for short periods. A balanced week usually spends most time in the lower zones with shorter bursts higher up, but the right mix depends on your goals and fitness.
Medical disclaimer: This calculator is for general information only and is not medical advice. The 220 minus age formula is a population average and individual maximums vary. Always consult a qualified doctor or healthcare professional before starting or changing an exercise programme, especially if you have a heart condition or take medication that affects your heart rate.
Frequently asked questions
How accurate is 220 minus age?
It is a useful average but only an estimate. Real maximum heart rates can sit roughly 10 to 12 beats per minute above or below the formula for a given age, so treat the result as a guide rather than an exact figure.
How do I find my resting heart rate?
Measure your pulse for a full minute when you first wake up, before getting out of bed, on a few mornings and take the average. Many fitness watches also track it automatically.
Why do my zones change when I add a resting rate?
With a resting heart rate the tool uses the Karvonen method, which is based on your heart-rate reserve rather than your maximum alone, so the bpm targets shift to suit your individual range.
Is my data uploaded?
No, everything is calculated on your device and nothing is sent anywhere.