Macro Calculator

Calculate your daily protein, carb, and fat targets based on your body, activity level, and fitness goal.

Four stages run in order. Your weight and height are converted to kilograms and centimetres if the unit toggles say pounds and inches; the Mifflin-St Jeor equation turns those plus age and sex into a basal rate (1,737 kcal at the defaults, with sex worth a flat 166 kcal); the activity multiplier scales that to a full-day expenditure; and only then does the goal adjust calories and choose a macro split. Because the goal enters last, BMR and TDEE are completely deaf to it — switch between fat loss and muscle gain and those two rows never budge while Daily Calories moves by 800. The single biggest lever on the answer is not any of the numeric fields, it is the Weight Unit toggle. Read as pounds, 170 gives 2,693 kcal; read as kilograms the same digits give 4,133, a 53 percent jump, and the Height Unit toggle is nearly as brutal — 70 centimetres instead of 70 inches drops the target to 1,649. Check both toggles before you trust anything below them. The splits are 35/35/30 for fat loss, 30/40/30 for maintenance and 30/45/25 for muscle gain, converted to grams at 4 kcal per gram for protein and carbohydrate and 9 for fat. One consequence catches lifters out: protein is a percentage of calories, not a function of body mass, so Protein per kg falls as you get heavier — 2.6 g/kg at 170 lb against 1.8 g/kg once the same profile weighs 170 kg. Nothing here accounts for body composition, medication or the roughly ten percent error band around any predictive metabolic equation.