Macro calculator
Enter your daily energy and choose a split. You get grams of protein, carbohydrate and fat, worked out with the standard calories per gram.
Updated 21 October 2026. Sources named on the page.
- Enter kilocalories or kilojoules
- Balanced, higher protein, lower carb or your own percentages
- Shows the working: 4 kcal per gram of protein and carbs, 9 per gram of fat
- Nothing you type is saved or sent
Work out your macros
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The formula and worked examples
Grams of a macro = daily calories x its percentage share / calories per gram. Protein and carbohydrate give 4 kcal per gram, fat gives 9 kcal per gram. The three shares must add up to 100.
Calories per gram
| Macro | kcal per gram | kJ per gram |
|---|---|---|
| Protein | 4 | 16.7 |
| Carbohydrate | 4 | 16.7 |
| Fat | 9 | 37.7 |
Worked examples at 2,000 kcal (8,368 kJ)
| Split | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced 20 / 50 / 30 | 100 g | 250 g | 66.7 g |
| Higher protein 30 / 40 / 30 | 150 g | 200 g | 66.7 g |
| Lower carb 30 / 30 / 40 | 150 g | 150 g | 88.9 g |
Sources: The 4, 4 and 9 kcal per gram figures are the standard Atwater energy factors; 1 kcal = 4.184 kJ
Figures and sources checked 21 October 2026. General information, not medical advice.
Questions
What are macros?
Macros, short for macronutrients, are protein, carbohydrate and fat: the three nutrients that give your body energy. A macro split says what share of your daily energy comes from each.
How are macro grams worked out?
Multiply your daily energy by the share for that macro, then divide by its energy per gram: 4 for protein and carbohydrate, 9 for fat. At 2,000 kcal and 20 percent protein that is 2,000 x 0.2 / 4 = 100 g.
Is there a best macro split?
No single split is best for everyone. The presets here are common examples, not recommendations. Your own needs depend on your health, goals and preferences.
How do I convert kilojoules?
Divide kilojoules by 4.184 to get kilocalories. Tick the box above and the calculator does it for you.
Who should not use this?
It is for adults aged 19 and over without a medical condition, and it is not medical advice. Ask a doctor or an accredited practising dietitian about your own needs.
Keep going
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