BMR & TDEE Calculator
Calculate basal metabolic rate and total daily energy expenditure using Mifflin-St Jeor.
Written by Anil Gautam · Updated
How does the Mifflin-St Jeor equation work?
BMR is 10 times your weight in kilograms, plus 6.25 times your height in centimetres, minus 5 times your age in years, then plus 5 for men or minus 161 for women. For a 30-year-old man who is 170 cm tall and weighs 70 kg: 700 + 1,062.5 - 150 + 5 = 1,617.5, shown as 1,618 kcal a day. A woman with the same measurements gets 1,452 kcal, because the two versions always differ by 166 kcal.
Each extra kilogram adds 10 kcal, each extra centimetre adds 6.25 kcal and each year of age takes 5 kcal off. The sliders move in whole steps: age from 15 to 90, height from 120 to 220 cm and weight from 30 to 200 kg.
Which activity level should you choose?
TDEE is BMR multiplied by an activity factor: 1.2 for sedentary, 1.375 for lightly active (the default), 1.55 for moderately active, 1.725 for very active and 1.9 for extra active. In the example, lightly active gives 1,617.5 × 1.375 = 2,224 kcal. This choice moves the result more than any other input. For a 35-year-old man of 175 cm and 80 kg, the five levels run from 2,069 to 3,275 kcal.
The labels count exercise days per week, so a schedule of two workouts a week fits lightly active and four fits moderately active. Treat the TDEE as a starting estimate and compare it with how your weight actually changes over a few weeks.
Where do the cutting and bulking targets come from?
Cutting is TDEE minus 500 kcal and bulking is TDEE plus 300 kcal, so the example shows 1,724 and 2,524 kcal. The weekly labels follow the common rule of thumb that a kilogram of body fat holds about 7,700 kcal: a 500 kcal daily gap adds up to 3,500 kcal a week, about 0.45 kg, and a 300 kcal surplus to about 0.27 kg.
Your BMR drops by 10 kcal for every kilogram you lose, so after 5 kg the lightly active TDEE is about 69 kcal lower and the same intake gives a smaller deficit. Re-enter your weight as it changes. The 500 kcal cut has no floor either: for a sedentary 60-year-old woman of 150 cm and 45 kg, BMR is 927 kcal, TDEE is 1,112 kcal and the cutting line reads 612 kcal, below her BMR. Discuss an intake that low with a doctor first. For protein, carb and fat grams, use the Calorie & Macro Calculator, which starts from the same equation.