How this macro calculator works
Your macronutrients — protein, carbohydrates and fat — are the three nutrients that supply the calories in your food. A macro split describes how your daily energy is divided between them, written as a set of percentages that add up to 100%. This calculator takes a daily calorie target and a split, then converts each share into grams.
The conversion uses the standard energy values: protein and carbohydrates supply about 4 calories per gram, and fat supplies about 9 calories per gram. For each macro it multiplies your calories by that macro's percentage to find the calories from that macro, then divides by the calories per gram to get the weight in grams. Finally it divides the daily grams by your meals-per-day to suggest a simple per-meal target.
| Macro | Calories / gram | % (balanced) | Grams @ 2,000 kcal |
|---|---|---|---|
| Protein | 4 | 30% | 150 g |
| Carbohydrates | 4 | 40% | 200 g |
| Fat | 9 | 30% | 67 g |
Reference note: the 4 / 4 / 9 calories-per-gram figures are the standard Atwater values used on nutrition labels. Rounding means the grams shown may differ by a calorie or two from your exact target.
Frequently asked questions
- What are macros?
- Macros, short for macronutrients, are the three nutrients that supply energy: protein, carbohydrates and fat. A macro split describes how your daily calories are divided among them, usually as a percentage of total calories.
- How do I calculate my macros?
- Start with a daily calorie target, then choose a percentage split for protein, carbs and fat that adds up to 100%. Multiply your calories by each percentage to get the calories from that macro, then divide by 4 for protein, 4 for carbs and 9 for fat to convert to grams.
- How many calories per gram of protein, carbs and fat?
- Protein has about 4 calories per gram, carbohydrates have about 4 calories per gram, and fat has about 9 calories per gram. These are the standard Atwater values used in nutrition labelling.
- What is a good macro split?
- There is no single best split. A balanced day is often around 30% protein, 40% carbs and 30% fat, while higher-protein, lower-carb or ketogenic patterns shift those percentages. The right split depends on your goals, activity and preferences.
- How much protein should I eat?
- General informational ranges often cited for healthy adults are roughly 0.8 to 2.0 grams of protein per kilogram of body weight per day, with more active people tending toward the higher end. Individual needs vary, so treat any figure as a starting point only.
- Is this medical advice?
- No. This calculator is for general information and education only. It is not medical or nutritional advice and does not replace guidance from a qualified doctor or dietitian. Speak with a professional before making changes to your diet.