How are heart rate training zones calculated?

The calculator uses the Karvonen (heart rate reserve) method, which factors in both your maximum and resting heart rate to personalise each zone, rather than a flat percentage of max heart rate alone.

What is the Karvonen formula?

The Karvonen formula sets a target heart rate from your heart rate reserve — the difference between your maximum and resting heart rate — multiplied by the intensity of the zone and added back to your resting heart rate. It produces more individualised zones than the percentage-of-max method.

Heart Rate Zone Calculator

Calculate personalised training heart rate zones using different methods

Calculation Method

Age only

No measurements needed. MHR = 220 − Age · THR = MHR × %

Age + resting heart rate (Karvonen)

More personalized — includes resting heart rate. MHR = 220 − Age · THR = (MHR − RHR) × % + RHR

Measured max heart rate (Karvonen)

Most accurate — uses your actual max heart rate. THR = (MHR − RHR) × % + RHR

Lactate threshold heart rate (Friel)

Zones from a 30-min field test. Most training-specific. THR = LTHR × %

MAF aerobic threshold (Maffetone)

Zones built around your aerobic ceiling. MAF = 180 − Age

Age

Resting Heart Rate (RHR)

Your Heart Rate Zones

Zone 1 — Recovery

50–60%

Very light effort — active recovery and warm-up

125–138

bpm

Zone 2 — Endurance

60–70%

Easy aerobic effort — builds base fitness and fat metabolism

138–151

bpm

Zone 3 — Tempo

70–80%

Moderate aerobic effort — improves cardiovascular efficiency

151–164

bpm

Zone 4 — Threshold

80–90%

Hard effort — raises lactate threshold and race pace

164–177

bpm

Zone 5 — VO₂max

90–100%

Maximum effort — develops peak aerobic capacity and speed

177–190

bpm

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