Macro Calculator (Protein, Carbs, Fat)
Calculate daily protein, carbohydrate, and fat targets for cutting, maintaining, or bulking. Supports keto, low-carb, and balanced diets.
What this calculates
Once you know your daily calorie target, macros decide how those calories split between protein, carbohydrate, and fat. Protein protects muscle on a cut and supports growth on a bulk. Fat supports hormones and satiety. Carbs fuel performance. This calculator builds a sensible default and lets you pick a diet style — balanced, low-carb, keto, or high-protein.
Formula & how it works
Protein: 1.6–2.2 g per kg of body weight (we use 1.8 for maintenance, 2.0 cutting, 1.6 bulking). Fat: balanced = 25 % of calories, low-carb = 35 %, keto = 70 %, high-protein = 25 %. Carbs fill the rest. Calories per gram: protein 4, carbs 4, fat 9. After computing protein grams and fat grams, carbs = (calories − protein × 4 − fat × 9) ÷ 4.
Worked example
A 75 kg adult, 2400 kcal/day maintenance, balanced diet. Protein = 75 × 1.8 ≈ 135 g (540 kcal). Fat = 25 % × 2400 ÷ 9 ≈ 67 g (600 kcal). Carbs = (2400 − 540 − 600) ÷ 4 = 315 g. So: 135 g protein, 315 g carbs, 67 g fat. On keto: protein stays at 135 g (540 kcal), fat = 70 % × 2400 ÷ 9 ≈ 187 g, carbs = (2400 − 540 − 1680) ÷ 4 = 45 g.
Frequently asked questions
Is high protein safe for healthy kidneys?
Yes for people without kidney disease. Decades of research show that 1.6–2.2 g/kg of body weight is safe and beneficial for adults with normal kidney function. People with existing kidney disease should follow their doctor's guidance.
How many carbs is 'keto'?
Strict keto is typically under 50 g net carbs per day, often under 30 g. Some people target ketosis within 20 g. Test strips or a glucose-ketone meter confirm if you're actually in ketosis — the count varies by individual.
Should I count fiber against carbs?
Fiber is technically a carb but has negligible glycemic impact. 'Net carbs' = total carbs − fiber − sugar alcohols. Most keto and low-carb diets count net carbs. Standard nutrition science still counts total carbs.
Why does protein matter on a cut?
When you eat below maintenance, your body looks for tissue to burn. Adequate protein plus resistance training signals it to spare muscle and burn fat instead. Without enough protein, a fraction of weight lost will be muscle — bad for metabolism and appearance.
Sources
Disclaimer: Informational only. Consult a registered dietitian for personalized planning, especially with medical conditions.