Calculate total daily energy expenditure from BMR and your activity level.
Total Daily Energy Expenditure is the number of calories your body burns in 24 hours including all activity. It's calculated by multiplying your Basal Metabolic Rate (the energy needed to keep you alive at rest, using Mifflin-St Jeor 1990) by an activity factor. Weight loss or gain is achieved by eating below or above this number — no calorie source behaves differently from another at the same deficit or surplus.
Mifflin-St Jeor BMR
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + S (S = +5 male, −161 female)
TDEE
TDEE = BMR × Physical Activity Level multiplier
This calculator provides estimates based on population-average equations. Individual metabolic rate varies by ±15–20%. These results are not medical or dietary advice — consult a registered dietitian or physician before making significant changes to your diet.
BMR (Basal Metabolic Rate) is the calories your body burns at total rest — just breathing, circulating blood and maintaining temperature. TDEE adds every calorie you burn from activity, digestion and daily movement. You eat relative to TDEE, not BMR.
A 2005 Journal of the American Dietetic Association meta-analysis found Mifflin-St Jeor predicted RMR within 10% for about 82% of subjects, compared to 72% for the revised Harris-Benedict. The older equation was derived from a small 1919 sample and tends to overestimate by 5–15%.
TDEE equations are population averages with ±15–20% individual variation. Use the result as a starting point: track your weight for 2–3 weeks at the calculated target, then adjust by 100–150 kcal if the trend doesn't match your goal.
A deficit of 500 kcal/day produces roughly 0.45 kg (1 lb) of weight loss per week, which is sustainable for most people. Deficits beyond 750–1000 kcal/day significantly increase lean-mass loss and metabolic adaptation.