Calorie Calculator - BMR & TDEE

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). See calories for weight loss, maintenance, and weight gain.

Calorie Calculator - BMR & TDEE Calculator

This calorie calculator uses two scientifically validated formulas to estimate your daily energy needs. The Mifflin-St Jeor equation, published in 1990, is considered the most accurate for most adults. The Harris-Benedict equation, revised in 1984, provides a comparison point. Both calculate your Basal Metabolic Rate (BMR) - the calories your body burns at complete rest - which is then multiplied by an activity factor to determine Total Daily Energy Expenditure (TDEE).

TDEE represents the total number of calories you burn in a day including all physical activity. For weight loss, a deficit of 500 calories per day results in roughly 0.5 kg (1 lb) of weight loss per week. For weight gain, a surplus of 500 calories supports muscle building when combined with resistance training. These are general guidelines - individual results depend on metabolism, body composition, and consistency.

The macronutrient breakdown uses a balanced 30/40/30 ratio (protein/carbs/fat) suitable for general health. Athletes, bodybuilders, or people following specific diets like keto or high-protein may need different ratios. Consult a registered dietitian for personalized nutrition advice. All calculations happen in your browser - your personal data is never stored or transmitted.

How the Calorie Calculator Works

  1. 01Select your unit system (metric or imperial) and gender
  2. 02Enter your age, weight, and height
  3. 03Choose your activity level from sedentary to very active
  4. 04View your BMR, TDEE, and calorie targets for weight loss, maintenance, and gain

Understanding BMR and TDEE

BMR (Basal Metabolic Rate) is the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production. TDEE (Total Daily Energy Expenditure) adds your physical activity on top of BMR. The Mifflin-St Jeor formula is generally considered the most accurate for healthy adults, while the Harris-Benedict formula tends to slightly overestimate. Both formulas account for gender, age, weight, and height.

When to Use a Calorie Calculator

Use this calculator when starting a weight management program, planning a diet, or trying to understand your daily nutritional needs. It is useful for setting realistic calorie targets whether you want to lose weight, maintain your current weight, or gain muscle mass. Athletes use TDEE to ensure they fuel their training adequately, while dietitians use BMR as a baseline for creating meal plans.

Common Use Cases

  • Setting calorie targets for weight loss, maintenance, or muscle gain programs
  • Planning meals and macronutrient distribution for fitness goals
  • Understanding your baseline metabolic rate for health assessments
  • Comparing BMR formulas to get a range of estimated calorie needs

Expert Tips

  • Recalculate your TDEE every 5-10 kg of weight change, as your calorie needs decrease as you lose weight
  • Be honest about your activity level - most people overestimate how active they are, leading to overeating
  • Use the macronutrient breakdown as a starting point, then adjust based on your specific goals and how your body responds

Frequently Asked Questions

What is the difference between BMR and TDEE?→
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest just to stay alive. TDEE (Total Daily Energy Expenditure) includes BMR plus all calories burned through physical activity, digestion, and daily movement. TDEE is always higher than BMR and is the number you should use for calorie planning.
Which formula is more accurate: Mifflin-St Jeor or Harris-Benedict?→
The Mifflin-St Jeor equation is generally considered more accurate for most adults, as it was developed more recently (1990) using modern data. The Harris-Benedict equation (revised 1984) tends to overestimate BMR by about 5%. This calculator shows both so you can see the range.
How many calories should I eat to lose weight?→
A daily deficit of 500 calories below your TDEE typically leads to about 0.5 kg (1 lb) of weight loss per week, which is considered a safe and sustainable rate. Eating below 1,200 calories (women) or 1,500 calories (men) per day is generally not recommended without medical supervision.
Does the calorie calculator account for body fat percentage?→
No, the Mifflin-St Jeor and Harris-Benedict formulas do not use body fat percentage. For people with very high muscle mass or very low body fat, the Katch-McArdle formula (which uses lean body mass) may be more accurate. For most people, the formulas used here provide a good estimate.
Is this calorie calculator free?→
Yes, completely free. All calculations run in your browser and your personal data (age, weight, height) is never sent to any server or stored anywhere.

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