Heart Rate Zone Calculator

Pure percentage multiplies your max heart rate by each zone's percentage, starting the scale from zero. Karvonen uses heart rate reserve (max HR minus resting HR), applies the zone percentage to that reserve, then adds resting HR back. Because Karvonen anchors every zone at your resting pulse, its targets land higher than the pure-percentage version. This calculator switches to Karvonen automatically once you enter a resting heart rate.

The 220 - age formula is a population estimate and can differ substantially from an individual's maximum heart rate. This calculator uses the Tanaka estimate (208 - 0.7 x age), which was developed from a large meta-analysis, but it is still an average. A professionally supervised graded exercise test can record your response to increasing workload. Do not use an all-out field session to establish a medical limit.

A five-zone model can help you describe easy, moderate, and hard sessions, but percentage bands based on estimated maximum heart rate do not prescribe a weekly plan. The appropriate mix depends on your sport, training history, recovery, goals, medications, and health. Use the ranges as training estimates and reduce or stop exercise for chest pain, faintness, unusual breathlessness, or other concerning symptoms.

Not necessarily. Modern optical wrist sensors are accurate enough for steady efforts in Zones 1-3. For Zone 4-5 interval work, where heart rate spikes and drops quickly, a chest strap responds faster and gives more reliable readings to help you stay on target.

This calculator builds zones from the Tanaka estimate, so it has no field for a measured max HR. Individual max HR can vary by 10-20 bpm from any formula even among people of the same age, so if a lab test or true max-effort field test gave you a different number, treat the zones here as a starting estimate. To match your tested value exactly, apply the same zone percentages to your own max HR by hand.