Calorie & TDEE Calculator
Estimate your daily calorie needs from the Mifflin-St Jeor equation, then adjust for your goal — lose, maintain or gain.
How calorie needs are calculated
Every calorie target starts from your BMR — the energy your body would burn lying still for 24 hours, powering your brain, heart, liver and body temperature. We estimate it with the Mifflin-St Jeor equation, the formula dietitians most often use because validation studies show it predicts measured BMR more accurately than older equations such as Harris-Benedict.
Real life burns more than BMR, so we multiply by an activity factor to get your TDEE — the calories that would keep your weight stable. Eating below TDEE loses weight; eating above it gains weight.
Worked example: a 30-year-old man, 80 kg and 180 cm: BMR = 800 + 1,125 − 150 + 5 = 1,780 kcal. If he is sedentary (×1.2), his TDEE is 2,136 kcal. To lose weight at a steady pace he would eat about 1,636 kcal per day; the calculator also suggests a protein-forward macro split (roughly 30% protein, 40% carbohydrates, 30% fat) to help protect muscle while dieting.
This tool gives general estimates for healthy adults and is not medical advice. If you are pregnant, under 18, or managing a medical condition, talk to a clinician or registered dietitian before changing your intake.
Frequently asked questions
What is the Mifflin-St Jeor equation?
It is the most widely validated formula for estimating resting metabolic rate: for men, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women, the same formula ends with − 161 instead of + 5. Research comparisons rate it the most accurate predictor for most adults.
What is the difference between BMR and TDEE?
BMR (basal metabolic rate) is the energy your body burns at complete rest just to stay alive. TDEE (total daily energy expenditure) multiplies BMR by an activity factor — from 1.2 for a sedentary desk worker to 1.9 for a very heavy training schedule — to estimate everything you burn in a day.
How many calories should I cut to lose weight?
A deficit of about 500 kcal per day below TDEE corresponds to roughly 0.45 kg (1 lb) of fat loss per week. This calculator never suggests targets below 1,500 kcal for men or 1,200 kcal for women, widely used safe minimums for unsupervised dieting.
Are these calorie numbers exact?
No — they are estimates, typically within about ±10% for individuals. Your real expenditure depends on muscle mass, hormones, sleep, medication and more. Use the number as a starting point, track your weight trend for 2–3 weeks, and adjust by 100–200 kcal as needed.