Calorie Calculator

How It Works

1. 1

   Enter your body stats

   Select your sex, then enter your age, height, and weight in metric or imperial units.

2. 2

   Choose your activity level

   Select the activity level that best describes your typical week — from sedentary to extra active.

3. 3

   Review your TDEE and macros

   See your estimated BMR (via two equations), TDEE, and caloric targets with macronutrient breakdown for weight loss, maintenance, and weight gain.

Understanding TDEE and Daily Calorie Needs

Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period, combining your Basal Metabolic Rate (BMR) with calories burned through physical activity. While BMR accounts for 60–75% of daily calorie expenditure in most adults, the activity multiplier transforms this resting value into a practical daily target. This calculator uses two respected equations for comparison: the Mifflin-St Jeor equation (1990), considered the most accurate for healthy adults, and the revised Harris-Benedict equation (Roza & Shizgal, 1984), one of the earliest and most widely cited BMR formulas. The Mifflin-St Jeor equation is used as the primary basis for TDEE because multiple validation studies show it comes within 10% of measured values for most individuals. For weight management, a deficit of 500 calories per day (about 1 lb/0.45 kg per week loss) is widely recommended as sustainable. The macronutrient breakdown uses a balanced 30/40/30 split (protein/carbs/fat) as a general starting point — athletes, those building muscle, or people with specific medical conditions may need different ratios. Always consult a registered dietitian for personalized macro targets.

Common pitfalls

• Activity multipliers are systematically overestimated. A desk job with three 45-minute gym sessions per week is lightly active (1.375x), not moderately active (1.55x). For a 2,000 kcal BMR that gap is 350 kcal/day, enough to decide whether you gain, hold, or lose weight at the same food intake.

• TDEE is a maintenance number, not a weight-loss target. A 500 kcal/day deficit below TDEE produces roughly 1 lb/week of fat loss at 3,500 kcal per pound. Eating at TDEE keeps weight flat.

• Adaptive thermogenesis reduces measured TDEE after prolonged calorie restriction. A 2016 follow-up on The Biggest Loser contestants (Obesity 24:1612) found resting metabolic rate stayed about 500 kcal/day below predicted values six years after the show. Recalculate TDEE after significant weight loss.

• NEAT varies by over 2,000 kcal/day between individuals at the same body weight. Non-exercise activity thermogenesis (Levine 1999, Science 283:212) covers fidgeting, standing, and pacing. A fitness tracker captures steps but misses most NEAT, so weight-trend over 2-3 weeks beats any formula output.

• Mifflin-St Jeor underestimates BMR in trained athletes with high lean mass and overestimates in sedentary individuals with high body fat. Track intake and weight for two weeks, then adjust calories based on the actual trend rather than the formula.

Frequently Asked Questions

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