You enter your age and resting heart rate. The tool estimates max heart rate using the standard 220−age formula, then applies the Karvonen method to calculate heart rate reserve (max HR minus resting HR). Each zone is a percentage range of HRR added back to resting HR. It assumes you know your true resting heart rate — measured first thing in the morning before getting out of bed.
It has a standard error of about ±10–12 bpm, meaning your actual max heart rate could be meaningfully different. If precision matters — for race pacing or clinical purposes — a graded exercise test gives a measured max HR.
Measure your pulse first thing in the morning, before caffeine or getting out of bed, for three consecutive days and average the results. A typical healthy adult resting HR is 60–80 bpm; trained endurance athletes may be 40–55 bpm.
Most endurance training plans call for 70–80% of total training volume in Zone 2 (aerobic base), with the remainder split between higher-intensity zones. This "polarized" or "80/20" approach is well-supported by research for improving aerobic fitness.
Yes — max HR while cycling is typically 5–10 bpm lower than while running, because cycling uses less total muscle mass. If you train in both sports, consider sport-specific zone calculations.
Tanaka et al. (2001) proposed 208 − 0.7 × age, which performs slightly better in older populations. Gulati et al. (2010) proposed 206 − 0.88 × age specifically for women. Both reduce prediction error compared to 220−age.
Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.