Calorie Needs Calculator
Find your BMR and total daily calorie needs from age, sex, height, weight, and activity level — using the Mifflin-St Jeor equation.
At rest your body burns about 1,699 kcal a day (BMR). Adjusting for your activity level, your total daily energy expenditure is 2,633 kcal — the calories you'd eat to maintain weight.
Daily calories by goal
Results update as you type. The Mifflin-St Jeor equation is the most accurate widely used formula at population level, but individual energy expenditure varies — treat the numbers as a starting estimate, not a prescription.
Formula
The Mifflin-St Jeor BMR equation:
BMR = 10·kg + 6.25·cm − 5·age + s, where
s = +5 for males, s = −161 for females. TDEE is BMR multiplied by
an activity factor (sedentary 1.2 → extra-active 1.9). Goal calories are TDEE shifted by
±500 or ±1000 — the latter giving roughly 1 kg of weight change per week (3,500 kcal ≈ 0.45
kg of fat).
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Frequently asked questions
What is BMR vs TDEE?▾
BMR (basal metabolic rate) is what you burn at full rest — heart beating, lungs breathing, body warm. TDEE (total daily energy expenditure) is BMR plus all activity: walking, working, exercise, NEAT (fidgeting, posture, etc.), and the thermic effect of food. TDEE is what you'd eat to maintain weight.
Mifflin-St Jeor vs Harris-Benedict — which is right?▾
Mifflin-St Jeor (1990). It replaced Harris-Benedict (1919, revised 1984) as the most accurate widely used formula. The American Dietetic Association's 2005 evidence review found Mifflin-St Jeor to be within 10% of measured BMR more often than any other simple equation. Katch-McArdle is more accurate but requires a body-fat percentage measurement most people don't have.
Why does the formula need my sex?▾
The equation has a sex-specific constant (+5 for males, −161 for females) reflecting average body-composition differences. It's a population-level shortcut. If your body composition doesn't fit the binary assumption — transgender adults on hormone therapy, very high muscle mass — treat the result as a rough starting point and adjust based on real-world weight changes.
How honest should I be about activity level?▾
Very. Most people overestimate by one bucket. 'Sedentary' is desk job + no structured exercise (the default for many Americans). 'Lightly active' is 1–3 gym sessions/week or consistent daily walking. 'Moderately active' is 3–5 proper workouts. 'Very active' is athletes or physical jobs. 'Extra active' is competitive training plus heavy labor. If you start at 'moderate' and aren't losing weight on the deficit it suggests, drop to 'lightly active' — your real expenditure is probably lower than you think.
Is 1,200 kcal the right minimum?▾
For most adult women yes; for adult men, 1,500 is more typical. Below those levels meeting micronutrient needs without supplementation gets difficult, and metabolism adapts down quickly. The NIH and academic dietetic associations recommend ≤500–750 kcal/day deficits for sustainable loss. Very low calorie diets (≤800 kcal/day) work but require medical supervision because of gallstone, electrolyte, and lean-mass risks.
What about pregnancy or breastfeeding?▾
Don't use this calculator unmodified. Pregnancy adds ~340 kcal/day in the second trimester and ~450 in the third; breastfeeding adds ~330–400 kcal/day for an exclusively-fed baby. Targets vary with prepregnancy BMI and the rate of weight gain — work with a clinician or RD rather than this tool.