Heart Rate Zones Calculator

Training by heart rate lets you match effort to your goal instead of guessing. The zones are simply bands of your maximum heart rate — the highest your heart can beat during all-out effort. Easy aerobic base work lives in the lower zones; hard intervals push into the top ones.

A common mistake is training too hard on easy days and too easy on hard days. Zones help you stay honest: keep recovery and long efforts in Zones 1–3, and save Zones 4–5 for genuine hard sessions. Most endurance plans spend the majority of time in the lower zones.

Your true maximum heart rate is individual, and the age-based estimate here can be off by about ±10 bpm. Use the zones as a starting framework, then adjust based on how efforts actually feel and, if you have it, data from a real max test.

Formula. Maximum heart rate = 208 − 0.7 × age (Tanaka). We then compute five zones as percentage bands of that maximum: Zone 1 (50–60%), Zone 2 (60–70%), Zone 3 (70–80%), Zone 4 (80–90%), and Zone 5 (90–100%).

Source. The Tanaka equation, published in the Journal of the American College of Cardiology in 2001, is more accurate across the adult age range than the traditional 220 − age. The five-zone percentages follow the widely used ACSM-style model.

Confidence. We label this moderate confidence: the age formula is a population estimate that varies between individuals, and the zone boundaries are practical training guides rather than exact physiological thresholds.