Heart Rate Zone Calculator
Calculate your 5 heart rate training zones from your age — runs entirely in your browser.
How heart rate zones are calculated
Heart rate zones divide your maximum heart rate (MHR) into five percentage bands, each targeting a different physiological effect. The Standard formula estimates MHR as 220 minus your age. The Tanaka formula uses 208 minus 0.7 times your age, which research shows is more accurate for adults over 40. Both formulas are population averages — your true MHR may vary by up to 10-12 beats per minute. Zone 1 (50-60%) is light recovery work; Zone 5 (90-100%) is all-out maximal effort. Calculations run entirely in your browser and nothing is sent to a server.
Training with zone awareness helps you balance stress and recovery. Most endurance athletes spend the majority of their training in Zones 1 and 2 (low intensity) to build aerobic base, with a smaller proportion in Zones 4 and 5 for speed and VO2 max adaptations. This approach, sometimes called polarised training, is supported by considerable sports science research.
FAQ
Which formula should I use? Standard (220 minus age) is the most widely cited and works as a quick reference. Tanaka is generally more accurate for people over 40 and produces a slightly lower MHR estimate. If you have done a supervised max-effort test, use that measured value instead.
Why do my zones feel off? Formula-based MHR is an estimate with meaningful individual variation. If Zone 2 feels too hard or too easy, consider a lactate threshold test or a graded exercise test with a sports physiologist to get personalised zones.