Daily Calorie Needs Calculator
Estimates your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation. Use it to plan calorie intake for weight loss, maintenance, or muscle gain based on your activity level.
About this calculator
This calculator uses the Mifflin-St Jeor equation to find your Basal Metabolic Rate (BMR) — the calories your body needs at complete rest — then multiplies by an activity factor to get your TDEE. For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. The activity multiplier ranges from 1.2 (sedentary) to 1.9 (very active). Your TDEE represents the total calories needed to maintain your current weight. To lose weight, eat below your TDEE; to gain, eat above it. The Mifflin-St Jeor formula is considered one of the most accurate for most non-athlete adults.
How to use
Suppose a 30-year-old male weighs 80 kg, is 175 cm tall, and exercises moderately (activity factor 1.55). Step 1 — Calculate BMR: 10 × 80 + 6.25 × 175 − 5 × 30 + 5 = 800 + 1093.75 − 150 + 5 = 1748.75 kcal. Step 2 — Multiply by activity level: 1748.75 × 1.55 = 2710.6 kcal/day. This man needs roughly 2,711 calories per day to maintain his weight. To lose ~0.5 kg per week, he would target about 2,211 calories daily.
Frequently asked questions
What is the difference between BMR and TDEE in a calorie needs calculator?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to sustain vital functions like breathing and circulation. TDEE (Total Daily Energy Expenditure) builds on that by factoring in your physical activity level. TDEE is always higher than BMR, and it's the more practical number for planning your diet. Most nutrition goals — weight loss, maintenance, or gain — are set relative to TDEE.
How accurate is the Mifflin-St Jeor equation for calculating daily calories?
The Mifflin-St Jeor equation is widely regarded as one of the most accurate BMR formulas for the general population, with studies showing it predicts measured BMR within about 10% for most people. Its main limitation is that it uses total body weight rather than lean mass, so it may slightly overestimate needs for people with higher body fat percentages and underestimate for very muscular individuals. For athletes, the Katch-McArdle formula, which uses lean body mass, can be more precise. For everyday use, Mifflin-St Jeor provides a reliable starting point.
How should I adjust my daily calorie needs for weight loss or muscle gain?
A common guideline is to create a 500 kcal/day deficit below your TDEE to lose approximately 0.5 kg (1 lb) per week, since roughly 3,500 kcal equals 0.45 kg of fat. For muscle gain, a modest surplus of 200–300 kcal above TDEE is often recommended to minimize fat gain. These are starting estimates — you should monitor your weight over 2–4 weeks and adjust intake accordingly. Individual metabolism, hormones, and food quality all influence actual results.