CalcVitalsMacro Calculator — Protein, Carbs & Fat in Grams
Macros are calories split by nutrient: protein and carbohydrate carry 4 kcal per gram, fat carries 9. At 2,556 kcal on a 30/40/30 split, that is 192 g protein, 256 g carbohydrate and 85 g fat a day.
How it works
Once total calories are set, macros are how you divide them. Protein is the non-negotiable slice: it preserves muscle in a deficit, drives growth in a surplus, and is the most satiating nutrient per calorie. Carbohydrate fuels training intensity; fat carries hormones, fat-soluble vitamins and a great deal of food satisfaction. The splits offered here span the range that research actually supports — there is no magic ratio hiding beyond them.
The arithmetic uses the standard energy values: 4 kcal per gram of protein, 4 per gram of carbohydrate, 9 per gram of fat. That is why fat grams always look small beside the others even at the same calorie share — each gram carries more than twice the energy, which is also why oils and butters change a meal's calories so quietly.
A word of proportion: decades of trials comparing low-carb, low-fat and balanced diets at equal calories and protein find near-identical fat loss. The split that works is the one built from food you enjoy enough to still be eating in six months. Pick the row that matches your table, not someone else's ideology.
The method
Protein grams = calories × protein% ÷ 4 kcal/g; carbohydrate the same ÷ 4; fat = calories × fat% ÷ 9 kcal/g. Splits are percentage of total energy. Fibre guide follows the 14 g per 1,000 kcal reference used in US dietary guidance.
Frequently asked questions
Which macro split is best for fat loss?
At equal calories and protein, fat loss is essentially the same across splits in controlled trials. Choose the split you can sustain; protect the protein number first (roughly 1.6–2.2 g per kg of body weight when dieting).
Do I need to hit every gram exactly?
No — treat them as daily targets with a ±10% working range. Weekly averages matter more than any single day, and fibre, micronutrients and food quality ride along when most choices are whole foods.
Why is keto's carb number so low?
Nutritional ketosis generally requires carbohydrate under about 50 g a day, which at most calorie levels is near 5% of energy. It is a specific metabolic strategy, not a requirement for fat loss.