Free Macro Calculator – Protein, Carbs & Fat Split

How the Macro Calculator Splits Your Calories into Grams

A calorie target tells you how much to eat but nothing about what. Two people eating 2,400 calories a day, one on 60 g of protein and one on 150 g, will end a twelve-week diet with visibly different bodies. Macronutrients are the three energy-carrying components of food, protein, fat, and carbohydrate, and splitting your calorie budget between them is what turns a number into a shopping list. This tool takes your daily calorie target and your body weight and returns a gram figure for each macro. That grams-per-day output is what makes it usable, because food labels and tracking apps speak in grams, not percentages. It is the arithmetic behind flexible dieting, often called IIFYM, and it is used by anyone logging food seriously: lifters in a cut, runners fuelling long weeks, and people who have been told to eat more protein without being given a number. The split runs in a fixed order, and the order matters. Protein comes first, anchored to your body weight at about 2 g per kilogram, because protein need scales with the size of your body rather than with your calorie budget. Multiply grams by 4 to get its calorie cost, since protein carries 4 calories per gram. Fat comes second, set at 25% of your total calories, then divided by 9 because fat is the densest macro at 9 calories per gram. That 25% floor exists for a reason: dropping fat too low disrupts hormone production and the absorption of vitamins A, D, E, and K. Carbohydrate takes whatever calories remain, divided by 4. So: protein g = weight × 2; fat g = calories × 0.25 ÷ 9; carb g = (calories − protein g × 4 − calories × 0.25) ÷ 4. Run a 75 kg lifter eating 2,400 calories. Protein is 75 × 2 = 150 g, costing 150 × 4 = 600 calories. Fat is 2,400 × 0.25 = 600 calories, which is 600 ÷ 9 = 66.7 g. That leaves 2,400 − 600 − 600 = 1,200 calories for carbohydrate, or 1,200 ÷ 4 = 300 g. Check it: 600 + 600 + 1,200 = 2,400, so the split accounts for every calorie. A second case, a 60 kg woman cutting on 1,800 calories: protein 120 g (480 calories), fat 1,800 × 0.25 = 450 calories or 50 g, carbohydrate (1,800 − 480 − 450) ÷ 4 = 870 ÷ 4 = 217.5 g. Four real uses. A 75 kg cricketer in pre-season sets 300 g of carbohydrate and finally has enough fuel for double sessions, having previously been on an accidental low-carb diet. A woman on 1,800 calories discovers her usual day contains only 70 g of protein and adds curd at breakfast and paneer at dinner to reach 120 g without changing her calories. Someone with a fatty liver diagnosis, told to cut refined carbohydrate, uses the tool to see exactly how many grams they were eating before adjusting. A couple splitting one 2,000-calorie meal plan work out that the 90 kg husband needs 180 g of protein while the 60 kg wife needs 120 g, so they portion the chicken differently rather than cooking twice. The mistake to avoid is treating these numbers as sacred. A 40/30/30 or 50/25/25 split is not magic; the ratios that matter most are adequate protein and total calories matching your goal, and the rest is preference and performance. Endurance athletes should push carbohydrate higher and fat toward the 20% floor. People who feel better on fewer carbohydrates can raise fat to 35% and pull carbs down, provided protein holds. What you cannot do is ignore accuracy: eyeballed portions routinely miss by 20 to 30%, and cooking oil is the single most under-counted item in home kitchens, at 9 calories a gram. Weigh food for the first two weeks until your estimates calibrate. Also remember that hitting macros says nothing about fibre, micronutrients, or food quality; 300 g of carbohydrate from lentils, rice, and fruit is not the same meal as 300 g from biscuits. These targets are general guidance, not medical or dietary advice, so consult a registered dietitian if you have diabetes, kidney disease, or any condition affecting nutrition. The calculation runs entirely in your browser, so your calories and weight are never uploaded or stored.

Macro Calculator Formula & Method

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