Training Science

Heart Rate Zone Calculator

Get your personalised 5-zone training ranges using the Karvonen (HRR) or classic 220−age formula.

Your Details

Age
In years
YRS
Resting Heart Rate
Required for Karvonen
BPM
Calculation Formula
Karvonen is more accurate if you know your resting heart rate.
Max HR (est.)
Resting HR
HR Reserve
Karvonen
Training Intensity Spectrum

Zone Reference Guide

About the 5 Zones

Zone% Max HRIntensityPrimary Benefit
Zone 1 — Recovery50–60%Very LightRecovery, blood flow
Zone 2 — Fat Burn60–70%LightFat metabolism, aerobic base
Zone 3 — Aerobic70–80%ModerateCardiovascular endurance
Zone 4 — Anaerobic80–90%HardLactate threshold, race pace
Zone 5 — Max Effort90–100%MaximumPeak speed, VO₂ max

Common Questions

What are heart rate training zones?

Training zones are percentage ranges of your maximum heart rate that correspond to different exercise intensities. Each zone produces distinct physiological adaptations — Zone 1 aids recovery, Zone 2 builds aerobic base and fat-burning efficiency, Zone 3 improves aerobic capacity, Zone 4 raises lactate threshold, and Zone 5 develops peak power and VO₂ max.

What is the Karvonen formula?

The Karvonen formula uses Heart Rate Reserve (HRR = Max HR - Resting HR). Target HR = RHR + (intensity% × HRR). Because it accounts for your resting HR, two people with the same max HR but different fitness levels get appropriately different zones. It is generally more accurate than the simple percentage method.

How is maximum heart rate estimated?

This calculator uses the standard formula 220 - age. Individual max HR can vary ±10–20 bpm from this estimate. For a more precise value, a graded exercise test in a clinical or sports-lab setting is the gold standard.

Which zone is best for fat burning?

Zone 2 is the "fat-burning zone" — fat is the primary fuel at this intensity. However, higher zones burn more total calories per minute even if a smaller proportion comes from fat. For fat loss, a mix of Zone 2 steady-state and higher-intensity intervals is most effective.