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Zone 2 heart rate calculator

This calculator gives you your zone 2 heart rate range in bpm, your estimated maximum heart rate, your Norwegian 4×4 interval zone and a recovery zone from your age and, optionally, your resting heart rate.

How it's calculated

Maximum heart rate is estimated with the Tanaka equation: 208 − 0.7 × age. Tanaka, Monahan and Seals (2001) developed it because the older 220 − age formula underestimated maximum heart rate in older adults. A 44-year-old gets an estimate of 177 bpm.

If you enter a resting heart rate, the zones use the Karvonen method: resting HR + a percentage × (max HR − resting HR). Zone 2 is 60–70%, the 4×4 zone is 85–95% and recovery is 50–60%. With a resting heart rate of 62, that 44-year-old's zone 2 is 131–143 bpm. Without a resting heart rate, the calculator uses the same percentages of maximum heart rate, which gives a lower range.

Every age-based formula is an estimate, and individuals can differ from it by 10 bpm or more. Check the result with the talk test: in zone 2 you can speak in full sentences but would rather not sing. Heat, caffeine, poor sleep and long sessions all push heart rate up, and beta-blockers push it down, so the numbers do not apply if you take them.

Want the zones turned into weekly sessions? The zone 2 plan builder uses the same numbers to write a 12-week plan with minutes, a long session and 4×4 days.

Frequently asked questions

Should I enter my resting heart rate?

Yes, if you can measure it reliably. The heart-rate reserve method fits your zones to your own fitness and usually gives a more useful range. Measure lying down on waking for three mornings, take the average and retest every four weeks, because a falling resting heart rate shifts your zones.

Why is my zone 2 so low?

Many people are surprised because their usual easy pace is above zone 2. If you skipped resting heart rate, the range is based on percentage of maximum and runs lower. If the range still feels far too easy, check it with the talk test, and consider a lab or field test of maximum heart rate.

Is this accurate enough to train with?

It is a good starting point, not a lab measurement. Use the bpm range together with breathing and the talk test, and adjust by a few beats if the two clearly disagree. A chest strap gives more reliable readings than a wrist sensor.

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General fitness information, not medical advice. Check with a doctor if you have a medical condition, are pregnant or have an injury.