How your macros are calculated
The calculator starts from your calorie target. It estimates your TDEE with the Mifflin-St Jeor equation and your activity level, then shifts it for your goal — about 500 calories below maintenance to lose, at maintenance to hold, or above to gain. That calorie number is then divided among the three macros by the split you choose, and each share is converted to grams using its energy density: protein and carbohydrate are 4 calories per gram, fat is 9. So a 2,000-calorie balanced plan at 30/40/30 works out to about 150 g protein, 200 g carbs and 67 g fat. Need the calorie number on its own first? Use the TDEE Calculator or the Calorie Deficit Calculator.
Picking a split that fits your goal
Balanced (30/40/30) is the reliable default and works for most people cutting, maintaining or gaining. Low-carb and high-protein lift protein and trim carbs, which helps protect muscle in a deficit and suits people who train hard or prefer fewer starches. Keto takes fat very high and carbs very low to keep the body running on ketones. Across every split the constant is protein — it is the macro most tied to keeping muscle and staying full, so the dedicated Protein Calculator is a useful cross-check.
Hitting macros without obsessing
Macros are targets, not exams. Landing within five to ten grams of each is plenty for real-world results, and total calories still do the heaviest lifting for weight change. Prioritise protein, spread it across your meals, then let carbs and fat flex around your appetite, training and schedule. Consistency over weeks beats precision on any single day.