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Calorie Calculator
Enter your sex, age, height, weight, and activity level to estimate your BMR (calories burned at rest) and TDEE (calories burned in a typical day), with calorie targets for losing, maintaining, or gaining weight. All figures are estimates from population equations, not measurements of your body.
Estimates only, for adults: the Mifflin-St Jeor equation predicts within roughly ±10% for most people, and real needs vary with muscle mass, health, and daily variation. Very low calorie targets should be discussed with a clinician — these are not medical advice.
How it works
Two steps. First, BMR (basal metabolic rate — calories burned at complete rest) from the Mifflin-St Jeor equation: men, BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5; women, the same with − 161 instead of + 5. Second, TDEE (total daily energy expenditure) = BMR × an activity multiplier: 1.2 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extremely active. Targets follow the rough rule that 500 calories/day ≈ 0.5 kg per week: lose = TDEE − 500, maintain = TDEE, gain = TDEE + 500. Worked example: a 30-year-old woman, 165 cm, 60 kg, moderately active → BMR = 10 × 60 + 6.25 × 165 − 5 × 30 − 161 = 600 + 1031.25 − 150 − 161 = 1,320 cal/day; TDEE = 1,320.25 × 1.55 = 2,046 cal/day; lose ≈ 1,546, maintain ≈ 2,046, gain ≈ 2,546 cal/day. Second check (male): 40 years, 180 cm, 80 kg, sedentary → BMR = 800 + 1125 − 200 + 5 = 1,730; TDEE = 1,730 × 1.2 = 2,076 cal/day. Estimates only — individual needs vary by roughly ±10%, and these are not medical advice.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is what you would burn lying still all day — keeping your body running. TDEE adds everything else: walking, working, exercise. TDEE is the number to eat against when planning weight change.
Why Mifflin-St Jeor and not Harris-Benedict?
Mifflin-St Jeor (1990) fits modern populations better than the 1919 Harris-Benedict equations, especially for overweight adults, and it is the equation most dietitians and the Academy of Nutrition and Dietetics use as a starting estimate.
How accurate is this?
Within about ±10% for most adults. Muscle mass is the big missing variable: two people of the same weight can differ by hundreds of calories a day. If your weight does not move after a few weeks at a target, adjust by 100–200 calories rather than trusting the number.
Why 500 calories for 0.5 kg a week?
A kilogram of body fat stores roughly 7,700 calories, so a 500-calorie daily deficit sums to 3,500 a week — about 0.45 kg. Real loss slows as you get lighter, so the rule is a starting approximation, not a guarantee.
Should I ever eat below my BMR?
Generally no without supervision: below-BMR targets are hard to sustain, risk nutrient shortfalls, and often backfire. If the lose target lands near or below your BMR, discuss it with a clinician or dietitian.