About the Macro Calculator
A calorie target alone doesn't say what to actually eat — it just says how much energy to take in. Macro Calculator takes your daily calorie target and splits it into the three macronutrients that make it up: protein, fat, and carbohydrates, each measured in grams per day rather than calories, since that's how most nutrition labels and food tracking apps report them.
Protein is calculated first, directly from your body weight and activity level — the same approach Protein Intake Calculator uses, since protein needs are driven by weight and training load rather than by how many calories you're eating. Fat is then set at 30% of your total calories, a practical midpoint within the commonly cited 20–35% range for dietary fat. Whatever calories remain after protein and fat are accounted for become your carbohydrate target.
Because protein and fat are set first, an unusually low calorie target combined with a high activity level can leave little or no room for carbohydrates — this calculator flags that case rather than ever showing a negative or broken carb number. Recalculate whenever your weight, activity level, or calorie goal changes, since every macro here is derived from those inputs.
Protein target based on the U.S./Canada Dietary Reference Intakes and sports-nutrition activity guidance; fat target based on the 20–35% Acceptable Macronutrient Distribution Range; calorie split uses standard Atwater factors (4/9/4 kcal per gram).