About the BMR calculator
Your basal metabolic rate is the energy your body needs to stay alive at complete rest: keeping your heart beating, your lungs working and your body temperature steady. For most people it makes up 60 to 70 percent of the calories they burn in a day.
Three equations are offered. Mifflin-St Jeor (1990) is the default and is considered the most accurate for most healthy adults. The revised Harris-Benedict equation is an older standard that tends to give slightly higher values. Katch-McArdle uses your lean body mass instead of age and sex, so it suits people who know their body fat percentage, especially athletes.
The table under the result multiplies your BMR by the usual activity factors to show how many calories you burn each day at each level of activity.
Formula
- Mifflin-St Jeor: 10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women)
- Harris-Benedict (men): 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age
- Harris-Benedict (women): 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age
- Katch-McArdle: 370 + 21.6 × lean mass (kg)
Example
A 25-year-old man who is 177.8 cm tall and weighs 72.57 kg has a Mifflin-St Jeor BMR of 10 × 72.57 + 6.25 × 177.8 − 5 × 25 + 5 = 1,717 calories a day. With the same data, Harris-Benedict gives 1,772 calories.