Target Heart Rate Calculator Formula

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

Use the Target Heart Rate Calculator

Formulas Used

Target Heart Rate

target_hr = hr_reserve * intensity + resting_hr

Max Heart Rate

max_heart_rate = max_hr

Heart Rate Reserve

heart_rate_reserve = hr_reserve

Variables

VariableDescriptionDefault
ageAge(years)30
resting_hrResting Heart Rate(bpm)65
intensityTarget Intensity0.7
max_hrDerived value= 220 - agecalculated
hr_reserveDerived value= max_hr - resting_hrcalculated

How It Works

Karvonen Formula

Target HR = (Max HR - Resting HR) x Intensity% + Resting HR

The Karvonen formula is more accurate than simple percentage methods because it accounts for your resting heart rate (heart rate reserve).

Max HR = 220 - Age

Worked Example

A 30-year-old with a resting HR of 65 bpm targeting 70% intensity.

age = 30resting_hr = 65intensity = 0.7
  1. 01Max HR = 220 - 30 = 190 bpm
  2. 02HR Reserve = 190 - 65 = 125 bpm
  3. 03Target HR = 125 x 0.70 + 65 = 152.5 bpm

Ready to run the numbers?

Open Target Heart Rate Calculator