Daily calorie needs are calculated with the Mifflin-St Jeor equation: BMR for men = 10×weight(kg) + 6.25×height(cm) − 5×age + 5 (women: −161 instead of +5), multiplied by an activity factor of 1.2–1.9. Example: a 30-year-old man, 70 kg, 175 cm, moderately active — BMR 1,649, about 2,556 kcal/day to maintain weight.
How is it calculated?
The calculation has two steps. First, compute the basal metabolic rate (BMR) — the calories your body burns at complete rest — using Mifflin-St Jeor: for men 10×weight (kg) + 6.25×height (cm) − 5×age + 5, and for women the same formula with −161 instead of +5. Then multiply the BMR by an activity factor: 1.2 for a sedentary lifestyle, 1.375 for light activity (1-3 workouts a week), 1.55 for moderate (3-5), 1.725 for high (6-7) and 1.9 for athletes or physically demanding jobs. The result (TDEE) is the calories needed to maintain your current weight.
Example: a 30-year-old man, 70 kg, 175 cm — BMR = 700 + 1,093.75 − 150 + 5 ≈ 1,649; at moderate activity: 1,649 × 1.55 ≈ 2,556 kcal/day. For weight loss the common guideline is a deficit of about 500 kcal/day (≈ 2,056 in the example), corresponding to roughly 0.5 kg per week; for weight gain, a similar surplus. Keep in mind: these are statistical estimates — individual metabolism can deviate by about 10%, and the formula is not adjusted for pregnancy, medical conditions or unusual body-fat levels.
Frequently asked questions
How many calories per day to lose weight?
The common guideline is a deficit of about 500 kcal/day below your maintenance calories (TDEE), which corresponds to losing roughly 0.5 kg per week. Example: a 30-year-old man, 70 kg, 175 cm, moderately active with maintenance of about 2,556 kcal — a target of about 2,056 kcal/day.
What is the difference between BMR and TDEE?
BMR (basal metabolic rate) is what your body burns at complete rest — 1,649 kcal in our example. TDEE is your total daily energy expenditure: BMR multiplied by an activity factor between 1.2 and 1.9 — at moderate activity, 1,649 × 1.55 ≈ 2,556 kcal/day.
How does the calculation differ for men and women?
In the Mifflin-St Jeor equation only the constant differs: men add 5, women subtract 161. With identical stats — age 30, 70 kg, 175 cm — a woman's BMR is about 1,483 kcal versus 1,649 for a man, a gap of 166 kcal per day.
The information on this site is a general estimate for informational purposes only, is not medical advice and is no substitute for consulting a doctor. Your data is never stored.
