Heart Rate Zone Calculator

If you're new to structured training: use MHR (Age). If you've been running consistently for 3+ months and know your resting HR: use Karvonen (Age + RHR). If you've done an all-out field test or a VO₂max test and know your actual max HR: use Karvonen (MHR + RHR) — this is the most accurate method and the one used by coaches.

HRR = Max HR − Resting HR. It represents the functional range your heart actually works within. Karvonen uses HRR instead of raw Max HR, so zones are calibrated to your current fitness level — a runner with a lower resting HR (more aerobically fit) gets different zones than someone with the same Max HR but higher resting HR.

The most reliable methods: (1) Check your Strava peak HR from an all-out race or a very hard effort at the end of a long run. (2) Run a 1-mile field test — warm up 15 min, then run the last 400m at absolute maximum effort. (3) A VO₂max lab test. Age formulas (like Tanaka: 208 − 0.7×age) are population averages with ±10–15 bpm standard deviation — not reliable for individuals.

Measure immediately after waking up, before standing or checking your phone. Lie still and count pulse for 60 seconds, or use overnight mode on a smartwatch. Average 3 consecutive mornings for best accuracy. Typical range: 50–70 bpm. Well-trained endurance runners: 40–55 bpm. A decreasing resting HR over weeks is a sign of improving aerobic fitness.