Calculate your daily caloric needs using Mifflin-St Jeor equation
🔥 How Many Calories Do You Need? Use the Mifflin-St Jeor equation—the most accurate formula for estimating your BMR (Basal Metabolic Rate). Your BMR is the calories your body burns at complete rest. Multiply by your activity level to get your TDEE (Total Daily Energy Expenditure).
The Mifflin-St Jeor equation, published in 1990, replaced the century-old Harris-Benedict equation as the gold standard — studies found it predicts resting metabolic rate more accurately across a wider range of body types.
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How It's Calculated: This calculator uses the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating BMR (Basal Metabolic Rate). Your BMR represents the calories your body burns at complete rest—essentially the energy needed to maintain basic functions like breathing, circulation, and cell production. We then multiply your BMR by an activity factor to determine your TDEE (Total Daily Energy Expenditure).
Categories Explained: Calorie needs vary significantly based on multiple factors. Sedentary individuals (little to no exercise) require fewer calories, while very active individuals (hard exercise or physical jobs) need substantially more. The activity multipliers range from 1.2 (sedentary) to 1.9 (extra active).
Limitations: While the Mifflin-St Jeor equation is the gold standard for estimating calorie needs, individual metabolism varies based on genetics, muscle mass, thyroid function, sleep quality, and stress levels. These calculations should be viewed as starting points, not absolute truths.
Using Your Results: Start with your "To Maintain" calorie number and track your weight over 2-3 weeks. If you want to lose weight, consume the "To Lose" calories. Re-calculate whenever your weight changes significantly or your activity level changes.
Metric example: A 30-year-old woman weighing 65 kg and 165 cm tall, moderately active: BMR = (10 × 65) + (6.25 × 165) − (5 × 30) − 161 = 650 + 1031.25 − 150 − 161 = 1,370 cal/day. TDEE = 1,370 × 1.55 = 2,124 cal/day to maintain, ~1,624 to lose, ~2,624 to gain.
Imperial example: A 30-year-old man weighing 180 lb (81.6 kg) and 5'10" (177.8 cm), moderately active: BMR = (10 × 81.6) + (6.25 × 177.8) − (5 × 30) + 5 = 816 + 1111.25 − 150 + 5 = 1,782 cal/day. TDEE = 1,782 × 1.55 = 2,762 cal/day to maintain, ~2,262 to lose, ~3,262 to gain.
Your BMR only accounts for calories burned at complete rest. Multiplying by an activity factor (1.2 for sedentary up to 1.9 for extra active) converts that into your TDEE — the calories you actually burn in a normal day, including movement and exercise.
It's considered the most accurate widely-used formula for estimating BMR in adults, but individual metabolism varies with genetics, muscle mass, thyroid function, sleep, and stress. Treat the result as a strong starting point, not an exact number.
A deficit or surplus of about 500 calories per day is a common target for roughly 1 pound of change per week, since one pound of body fat is roughly 3,500 calories. This calculator applies that ±500 adjustment to your maintenance number automatically.