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 MaxPurpose 150-60%Warm up, recovery 260-70%Fat burning 370-80%Aerobic / cardio 480-90%Anaerobic threshold 590-100%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

Frequently Asked Questions

How accurate is the 220 minus age formula?

It provides a reasonable estimate for most people, but individual max HR can vary by 10-20 bpm. A stress test provides a more accurate measurement.

Learn More

Guide

Heart Rate Zones Explained: Train Smarter with Zone-Based Exercise

Learn about the five heart rate training zones, how to calculate them, and how to use zone-based training to improve endurance, burn fat, and boost performance.

Ready to run the numbers?

Open Heart Rate Calculator