Calorie Calculator
Estimate your daily calorie needs using the Mifflin-St Jeor equation. Enter your age, sex, weight, height, and activity level to see your BMR, maintenance calories, and estimated targets for weight loss or gain.
Sex
Educational tool only. Calorie estimates are based on statistical equations and population averages. Individual metabolism varies. These results do not constitute medical or dietary advice. Consult a registered dietitian or healthcare provider for personalized nutrition guidance.
What Is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body needs at complete rest to sustain vital organ function — breathing, blood circulation, cell production, and maintaining body temperature. It represents the largest portion of most people's daily calorie burn, typically 60–75% of total expenditure.
Mifflin-St Jeor Formula
Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161 TDEE = BMR × Activity Multiplier Activity Multipliers: Sedentary (little/no exercise) × 1.2 Lightly Active (exercise 1–3 days/wk) × 1.375 Moderately Active (exercise 3–5 days/wk) × 1.55 Very Active (hard exercise 6–7 days/wk) × 1.725 Extra Active (physical job + training) × 1.9 Example: Male, 30 yrs, 75 kg, 175 cm, moderately active: BMR = (750) + (1,093.75) − (150) + 5 = 1,698.75 kcal TDEE = 1,698.75 × 1.55 ≈ 2,633 kcal/day
Understanding TDEE and Weight
TDEE (Total Daily Energy Expenditure) is your maintenance calorie level — the number of calories you need to eat to keep your weight stable. Consistently eating below TDEE creates a calorie deficit, which leads to weight loss. A 500-calorie daily deficit produces roughly 0.5 kg (1 lb) of weight loss per week — the widely cited safe rate.
The activity multiplier is the most difficult part of the equation to estimate accurately. Most people overestimate their activity level. If your weight is not changing as expected, try the next lower activity category and adjust from there.
Frequently Asked Questions
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain vital functions — breathing, circulation, cell production, and temperature regulation. It represents roughly 60–75% of total daily calorie expenditure for most people.
What is TDEE?
TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor. It estimates the total calories you burn in a day including exercise and movement. Eating at your TDEE maintains your current weight. Eating below TDEE creates a calorie deficit for weight loss.
How accurate are Mifflin-St Jeor calorie estimates?
The Mifflin-St Jeor equation (developed in 1990) is widely considered the most accurate BMR formula for most adults, typically within 10% of measured BMR in laboratory settings. It is recommended by the Academy of Nutrition and Dietetics. However, it does not account for body composition — a muscular person will burn more calories than the formula predicts.
How much of a calorie deficit should I eat at?
A 250–500 calorie daily deficit is generally recommended for sustainable weight loss. Very low calorie diets (1,200 kcal or below for women, 1,500 kcal or below for men) can cause muscle loss, nutrient deficiencies, and metabolic adaptation. A conservative deficit produces slower but more sustainable results.
Why does muscle mass matter for calorie burn?
Muscle tissue is metabolically active — it burns more calories at rest than fat tissue. Two people of the same weight and height can have significantly different BMRs depending on their body composition. This is why strength training supports fat loss: it preserves or builds muscle while dieting, preventing metabolic slowdown.
Want the full explanation? Read the Calorie Calculator Guide →