Calorie Calculator

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at rest for basic functions like breathing, circulation, and temperature regulation. It is the starting point for estimating your total daily calorie needs, since every activity you add during the day sits on top of this baseline.

A common starting point is about 500 kcal a day below your TDEE, which may produce roughly 0.5 kg (1 lb) of weight loss per week for many adults. A larger deficit of around 1,000 kcal a day is sometimes used for faster loss, though individual results vary and larger deficits are harder to sustain.

The Mifflin-St Jeor equation is generally considered more accurate for modern adults and is the formula most calculators default to today. The older Harris-Benedict equation tends to overestimate calorie needs slightly. No formula is perfect for every body, but Mifflin-St Jeor is a solid practical starting point.

Common reasons include underestimating portion sizes, overestimating exercise calories, water retention, inconsistent tracking, or a slowing metabolism as body weight drops. Recalculating your numbers every few weeks and tracking consistently for a longer stretch usually clears this up.

Protein needs vary by body weight, activity level, and goal. Active people, and anyone trying to build or preserve muscle, generally benefit from higher protein than sedentary individuals. This calculator uses a balanced 30% protein macro split as a simple, general-purpose estimate.

Very low calorie diets can raise the risk of nutrient deficiency, fatigue, muscle loss, and gallstones, and they are usually hard to sustain. Anyone considering a very low calorie approach should do so under medical supervision rather than relying on a calculator alone.

This calculator is built for adults. Children and teenagers have different, growth-related energy needs, so a pediatrician or registered dietitian is a better source of guidance than an adult calorie calculator.

Macronutrients are protein, carbohydrates, and fat — the three nutrients that make up your calorie total. Tracking them can help balance energy, muscle support, and fullness, but beginners often do better focusing on total calories first and adding macro tracking once that habit is steady.