Calorie Calculator

Your daily calorie needs depend on your Basal Metabolic Rate (BMR) — the energy your body requires at complete rest — multiplied by an activity factor. The Mifflin-St Jeor equation is the most accurate formula for estimating BMR, and it accounts for your age, sex, height, and weight to produce a personalized calorie target.

The Mifflin-St Jeor formula was published in 1990 and has been validated in numerous clinical studies as more accurate than the older Harris-Benedict equation, which was developed in 1918. For men, the formula is (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5. For women, the formula subtracts 161 instead of adding 5. This calculator applies the appropriate formula based on your inputs and multiplies by the correct activity factor to produce your Total Daily Energy Expenditure (TDEE), which is the actual number of calories you should plan your meals around.

To lose weight, you need a calorie deficit — consuming fewer calories than you burn. A deficit of 500 calories per day leads to approximately one pound of weight loss per week. For weight gain, a surplus of 250-500 calories per day supports muscle growth when combined with resistance training. Extreme deficits below 1,200 calories are not recommended.

The rate at which you lose weight is not always linear. During the first week or two of a caloric deficit, your body sheds water weight rapidly, which can create the illusion of faster progress than is actually occurring. After this initial phase, fat loss stabilizes at roughly one pound per 3,500-calorie cumulative deficit. Metabolic adaptation — where your body reduces energy expenditure in response to prolonged dieting — means you may need to periodically recalculate your calorie target every 10-15 pounds lost or adjust your activity level upward to maintain the same rate of loss.

Your activity level significantly impacts total daily energy expenditure. A sedentary person may burn 1,800 calories daily while a very active person of the same size may burn over 3,000. Accurately assessing your activity level is crucial for setting the right calorie target.

Most people overestimate their activity level, which leads to calorie targets that are too high for their goals. Sedentary means desk work with no intentional exercise. Light activity includes 1-3 days per week of walking or light gym sessions. Moderate activity means 3-5 days of structured exercise like running, swimming, or strength training for 30-60 minutes. Active and very active levels are reserved for people who exercise intensely 6-7 days per week or have physically demanding jobs like construction or warehouse work. If you are unsure, start with a lower activity estimate and adjust upward based on actual results over 2-3 weeks.

Once you know your calorie target, distributing calories among protein, carbohydrates, and fats optimizes results. A common balanced split is 30% protein, 40% carbohydrates, and 30% fat. Adjust based on your specific goals — higher protein for muscle building, moderate carbs for endurance athletes.

Protein is the most important macronutrient for body composition because it preserves lean muscle during weight loss and stimulates muscle protein synthesis during weight gain. Research consistently shows that 0.7 to 1.0 grams of protein per pound of body weight is optimal for most active individuals. Carbohydrates fuel high-intensity exercise and brain function, while dietary fats are essential for hormone production and nutrient absorption. Tracking your macronutrient intake for even a few weeks builds an intuitive understanding of portion sizes that serves you well even after you stop counting.