Calories Burned by Heart Rate Calculator
Estimate calories burned during exercise from your average heart rate, age, weight, sex and duration using the Keytel (2005) equations used by many fitness watches.
How it works
Men: kcal/min = (−55.0969 + 0.6309 × HR + 0.1988 × W + 0.2017 × A) ÷ 4.184 · Women: kcal/min = (−20.4022 + 0.4472 × HR − 0.1263 × W + 0.074 × A) ÷ 4.184 (HR bpm, W kg, A years) · calories = kcal/min × minutes
Keytel and colleagues (2005) measured heart rate and oxygen uptake in 115 regularly exercising adults and fitted separate equations for men and women that predict energy expenditure in kJ per minute; dividing by 4.184 converts to kcal. Because heart rate rises roughly linearly with oxygen uptake during steady aerobic exercise, it tracks effort better than distance or time alone. The equations are designed for continuous exercise between about 90 and 180 bpm and are less reliable for weight training, intervals, heat or stress.
Worked example
A 35-year-old man weighing 70 kg exercises for 45 min at an average of 140 bpm: (−55.0969 + 0.6309 × 140 + 0.1988 × 70 + 0.2017 × 35) ÷ 4.184 = 54.20 ÷ 4.184 = 13.0 kcal/min, so 13.0 × 45 = 583 kcal.
Frequently asked questions
How do I calculate calories burned from heart rate?
Use the Keytel equation for your sex with your average heart rate, weight and age to get kcal per minute, then multiply by the duration. Average heart rate from a chest strap or watch over the whole session works best.
Why do men and women have different equations?
At the same heart rate, men on average have larger hearts and more muscle, so they move more oxygen per beat and burn more energy. Fitting the sexes separately gave noticeably better accuracy in the original study.
Is my fitness watch more accurate?
Many watches start from similar heart-rate equations and add your VO2max or resting heart rate. Expect any heart-rate method to be within about ±15–20% for steady cardio and less accurate for strength training or interval workouts.
Does this include calories I would burn at rest?
Yes, it is a gross estimate. For a 70 kg adult, resting metabolism is about 1.2 kcal per minute, so subtract roughly that if you want only the extra calories from exercise.
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This calculator gives an estimate for general fitness and education only. It is not medical advice — prediction equations can differ from measured values, so talk to a doctor or qualified exercise professional before changing your training, especially if you have a heart condition or take medication.