Heart Rate Zones Calculator

Estimating your maximum heart rate

Training zones start from your maximum heart rate (max HR), the highest number of beats per minute your heart can reach during all-out effort. The classic estimate is 220 − age. A widely cited alternative is the Tanaka formula, 208 − 0.7 × age, which was derived from a large meta-analysis and fits older adults better. For a 40-year-old both give 180 bpm, but for a 60-year-old the classic formula gives 160 while Tanaka gives 166. If you have measured your real max during a supervised test, choose the custom option and enter it.

% of max versus Karvonen zones

With the simple method each zone is a percentage of max HR: zone 1 is 50–60%, zone 2 is 60–70%, zone 3 is 70–80%, zone 4 is 80–90% and zone 5 is 90–100%. The Karvonen method is more personal. It first finds your heart rate reserve, max HR − resting HR, and then calculates target = reserve × intensity % + resting HR. For a max of 180 and resting rate of 60, the reserve is 120, so 60% intensity gives 120 × 0.6 + 60 = 132 bpm. Fitter people have a lower resting heart rate, so their zones shift and widen accordingly.

How to use the five zones

Most of your volume is usually spent in zones 1 and 2, where you can talk comfortably and recover quickly. Zone 3 builds aerobic capacity, zone 4 improves speed and lactate threshold, and zone 5 is for short, hard intervals. Heart rate also drifts with heat, dehydration, caffeine, stress and lack of sleep, so combine the numbers with how the effort actually feels. This page is for general information only and is not medical advice; see a doctor before starting vigorous exercise, particularly if you have a heart condition or take medication that affects heart rate. All calculations run locally in your browser and nothing is uploaded.