Calorie Needs Calculator

Formula Explanation

This calculator estimates your daily calorie needs in two main steps:

1. Calculate BMR (Basal Metabolic Rate): This is the number of calories your body burns just to stay alive (breathing, circulating blood, etc.) if you were to do nothing but rest all day. This calculator uses the Mifflin-St Jeor Equation, which is considered highly accurate.
   • Male Formula: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
   • Female Formula: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
2. Calculate TDEE (Total Daily Energy Expenditure): This is your Maintenance Calories. It takes your BMR and multiplies it by an Activity Factor based on how active you are. This final number is the total calories you burn in a typical day, including all your movements and exercise.
   • Formula: TDEE = BMR × Activity Factor
   • Example: If your BMR is 1,500 and you are "Lightly Active" (factor of 1.375), your TDEE is 1,500 × 1.375 = 2,063 calories per day. This is the amount you would eat to maintain your current weight.

The other results ("Mild Loss" and "Mild Gain") are simply your TDEE (Maintenance Calories) with 250 calories subtracted or added, which typically corresponds to a weight loss or gain of about 0.25kg (or 0.5 lbs) per week.