Heart Rate Calculator Formula

Understand the math behind the heart rate calculator. Each variable explained with a worked example.

Use the Heart Rate Calculator

Formulas Used

Max Heart Rate

max_heart_rate = max_hr

Zone 1 - Warm Up (50-60%)

zone1 = max_hr * 0.5

Zone 2 - Fat Burn (60-70%)

zone2 = max_hr * 0.6

Zone 3 - Cardio (70-80%)

zone3 = max_hr * 0.7

Zone 4 - Hard (80-90%)

zone4 = max_hr * 0.8

Zone 5 - Max (90-100%)

zone5 = max_hr * 0.9

Variables

VariableDescriptionDefault
ageAge(years)30
max_hrDerived value= 220 - agecalculated

How It Works

Maximum Heart Rate Formula

Max HR = 220 - Age

This is the most widely used formula for estimating maximum heart rate.

Heart Rate Zones

| Zone | % of Max | Purpose | |---|---|---| | 1 | 50-60% | Warm up, recovery | | 2 | 60-70% | Fat burning | | 3 | 70-80% | Aerobic / cardio | | 4 | 80-90% | Anaerobic threshold | | 5 | 90-100% | Maximum effort |

Worked Example

A 30-year-old person.

age = 30
  1. 01Max HR = 220 - 30 = 190 bpm
  2. 02Zone 2 (fat burn) = 190 x 0.60 = 114 bpm to 190 x 0.70 = 133 bpm
  3. 03Zone 3 (cardio) = 190 x 0.70 = 133 bpm to 190 x 0.80 = 152 bpm

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