How this calculator works
This calculator uses the Mifflin-St Jeor equation, published in 1990 and generally the most accurate of the common formulas for estimating resting energy needs in healthy adults. Enter your stats, pick an activity level, and read your maintenance calories from the table.
TDEE is the number to plan around: eat roughly at it to maintain weight, about 500 calories under for a steady ~1 lb (0.45 kg) per week of loss, or above it to gain. Remember these are population estimates — individual metabolisms vary, so adjust based on what the scale actually does over a few weeks.
These figures are population averages, not medical advice. If you're pregnant, have a thyroid or other metabolic condition, or are planning a significant, sustained change in calorie intake, check with a doctor or registered dietitian before using this number for anything more than a rough starting point.
The Mifflin-St Jeor equation
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161TDEE = BMR × activity factor (1.2 sedentary … 1.9 extra active)Worked example: man, 30, 80 kg, 180 cm, moderately active
- BMR = 10×80 + 6.25×180 − 5×30 + 5 = 800 + 1,125 − 150 + 5 = 1,780 kcal/day.
- Moderate activity factor is 1.55.
- TDEE = 1,780 × 1.55 ≈ 2,759 kcal/day to maintain current weight.
Frequently asked questions
Which activity level should I pick?
Most people overestimate. Desk job with no training is sedentary (1.2); training 3–5 days a week is moderate (1.55). If you sit all day and lift three times a week, light-to-moderate is usually closer to reality than 'very active'.
Why Mifflin-St Jeor instead of Harris-Benedict?
Validation studies since the 1990s have found Mifflin-St Jeor predicts measured resting energy expenditure more accurately in modern populations. Harris-Benedict (1919) tends to overestimate by roughly 5%.
Is BMR the same as the calories burned sleeping?
Close but not identical. BMR is measured at complete rest, awake, fasted, in a neutral-temperature room. Sleep burns slightly below BMR; ordinary sitting slightly above.
How fast can I safely lose weight?
A deficit of 500 kcal/day gives about 1 lb (0.45 kg) per week, a commonly recommended pace. Larger deficits increase muscle loss and are harder to sustain; consult a professional before going beyond that.
How much does my calculated BMR change per kilogram of body weight?
Exactly 10 kcal/day per kilogram. The Mifflin-St Jeor equation multiplies weight by a fixed factor of 10, independent of height, age or sex, so any change in the weight you enter shifts the calculated BMR by 10 kcal/day for every kilogram, all else being equal.