Heart Rate Zone Calculator

Calculate cardio training zones based on your max heart rate. Find zones for fat burn, endurance, threshold, and VO2 max. Free and privacy-first.

) was derived from a 2001 meta-analysis of 18,712 subjects and is now the standard. For best accuracy, replace the estimate with your actual max from a graded exercise test or a hard 5K race." }} />

What Each Zone Does

Zone 1 (50–60%) — recovery walks, warmups. Zone 2 (60–70%) — aerobic base, fat oxidation, the workhorse of marathon training. Zone 3 (70–80%) — tempo. Zone 4 (80–90%) — lactate threshold, the zone you can sustain for ~1 hour. Zone 5 (90–100%) — VO₂ max intervals, 30s–4min repeats. Most amateurs spend too much time in Zone 3 and not enough in Zones 2 and 5." }} />

The 80/20 Rule

More Frequently Asked Questions

Is this medical advice?

No. The zones are general training guidance. Consult a doctor before starting intense exercise, especially over 40 or with cardiac history.

Why are my zones different in Garmin?

Garmin and Polar offer multiple zone methods (Tanaka, Karvonen, %HRR). Switch your watch to '%HR Max — Tanaka' for matching values.

Should I use measured max or estimate?

Measured is more accurate. A maximal-effort 5K, hill repeat session, or supervised treadmill test gives a real number.

What is Karvonen?

Karvonen uses heart-rate reserve

. It accounts for resting heart rate, useful for very fit athletes whose RHR is well below average.

Is anything saved?

No. All math happens locally; nothing is transmitted.