Zone 2 heart rate calculator

Calculate a heart-rate range from your measured maximum and a chosen percentage definition of zone 2.

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Your measured maximum heart rate (bpm)

Lower percentage of maximum

More inputs and assumptions

Upper percentage of maximum

Answer

…

Calculate a heart-rate range from your measured maximum and a chosen percentage definition of zone 2.

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Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

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Formula and assumptions

Defaults use Polar's five-zone convention, 60-70 percent of maximum heart rate. Other systems define zone 2 differently. This arithmetic range is not a measured lactate or ventilatory threshold, exercise clearance or a safe-intensity prescription. Use an existing maximum measurement and the range appropriate to your training or clinical guidance.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-29

Using Zone 2 heart rate calculator

Calculate a heart-rate range from your measured maximum and a chosen percentage definition of zone 2.

Next: Target heart rate calculator

Next: VO2 max calculator

A worked example

For your measured maximum heart rate (bpm) = 180, lower percentage of maximum = 60, upper percentage of maximum = 70, lower heart-rate boundary (bpm) = 108.

Before you use the result

Example results for your measured maximum heart rate (bpm)

These examples use Lower percentage of maximum: 60; Upper percentage of maximum: 70. They are reference calculations, not recommended settings.

Your measured maximum heart rate (bpm)	Lower heart-rate boundary (bpm)
90	54
180	108

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