Heart Rate Calculator – Max HR and Target Zones
Free heart rate calculator: enter your age to get your estimated maximum heart rate and training zones (50%, 60%, 70%, 80%, 90%). Based on the Fox formula. For cardio, running and fitness. No sign-up, runs in your browser.
Heart Rate Calculator
Enter your age to estimate max heart rate and target zones (50–90% of max).
How the heart rate calculator works
Max HR = 220 − age (Fox formula). Each zone is that percentage of max HR. For example, at age 30: max HR = 190; zone 70% = 133 bpm. Use these numbers to guide your training intensity.
Using heart rate zones for training
Heart rate zones help you train at the right intensity. Low-intensity work (zone 1–2) builds endurance and burns fat. Moderate intensity (zone 3) improves aerobic fitness. High intensity (zone 4–5) boosts speed and power but should be used sparingly. Most training plans recommend spending most time in zones 2–3, with shorter bursts in zone 4.
The 220 − age formula was popularized by Dr. William Haskell and Dr. Samuel Fox in the 1970s. While not perfect for every individual, it remains widely used because it is simple and works reasonably well for population averages. If you take medications that affect heart rate (e.g. beta-blockers), your actual max HR may differ. Consult your doctor before starting intense exercise.
Pair this calculator with our calorie calculator to estimate how many calories you burn during exercise, and our BMR calculator to understand your baseline metabolism. Together they help you plan nutrition and training for your goals.