Estimates only, based on the Mifflin-St Jeor equation. Not medical advice. Adults only.
About this tool
Macros are the three nutrients that supply calories: protein, carbohydrates and fat. This macro calculator estimates your daily calorie target from your size and activity, adjusts it for your goal, and turns it into grams of protein, carbs and fat using a split you choose. It runs in your browser and nothing is stored.
How to use it
Enter your details, pick a goal and choose a split. The result shows total calories and the grams of each macro. Try the three splits to see how the numbers move. If you only want calories, use the calorie calculator.
How the grams are calculated
Protein and carbohydrate each provide 4 calories per gram, and fat provides 9. So calories from each macro are divided by those values. For a 2,000 calorie day on a balanced 40/30/30 split, carbs are 800 calories (200 g), protein is 600 calories (150 g) and fat is 600 calories (about 67 g). The three shares always add up to your calorie target.
The splits offered
- Balanced (40% carbs, 30% protein, 30% fat): a flexible starting point for most people.
- High protein (30% carbs, 40% protein, 30% fat): often chosen during weight loss to help with fullness and to preserve muscle.
- Lower carb (25% carbs, 35% protein, 40% fat): suits people who feel better with fewer carbs.
Important limits of any calorie calculator
These numbers are estimates. The equation is based on averages, and real needs differ by muscle mass, genetics, medications and health conditions. Use the result as a starting point, track your weight over two to three weeks, and adjust. Do not eat below the minimum shown without medical supervision, and speak to a doctor or registered dietitian before making big changes, especially if you are pregnant, breastfeeding, under 18, or managing a health condition. This tool is for adults.
Things to watch out for
There is no single ideal split, and total calories matter more than the exact ratio for weight change. Protein needs are also often expressed per kilogram of body weight, so a percentage split may give a low or high figure for very small or large people. Fibre, vitamins and food quality are not captured by macros alone. Treat these grams as targets to adjust, not strict rules.
Frequently asked questions
Protein and carbohydrates provide about 4 calories per gram, and fat provides about 9 calories per gram.
There is no single best split. A balanced split of 40% carbs, 30% protein and 30% fat is a common starting point, and people adjust it based on preference, goals and how they feel.
No. Total calories drive weight change. Tracking macros can help with protein intake and food choices, but it is optional.