Heart Rate Zone Calculator

Five training zones, using either %MaxHR or the Karvonen heart-rate reserve method. Enter your max HR if you know it, or estimate it from your age.

Age-based estimates are approximations — real Max HR can vary by ±10–15 bpm. The most accurate value comes from a maximum-effort field test or lab test. Karvonen better reflects real exercise intensity than %MaxHR alone.

How this is calculated

% MaxHR: each zone band is a fixed percentage of your Max HR. Z1 = 50–60 %, Z2 = 60–70 %, Z3 = 70–80 %, Z4 = 80–90 %, Z5 = 90–100 %.

Karvonen (heart-rate reserve): target = (HR_max − HR_rest) × intensity + HR_rest. Same percentages, applied to the gap between resting and max heart rate. This better matches actual exercise intensity, especially for fit athletes with low resting heart rates.

If you don’t know your Max HR, Tanaka (208 − 0.7 × age) has better evidence in older athletes than the older Fox formula (220 − age).