Macros to Calories Calculator
Turn grams of protein, carbohydrates, fat and alcohol into calories. See the total, the calories from each macronutrient, the percentage split as a pie chart and the formula with your numbers.
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Total carbs, including fiber and sugar
Compare with the nutrition label
How to use the Macros to Calories Calculator
- Enter grams of protein, carbohydrates and fat (and alcohol if any).
- Set the number of servings if you ate more than one.
- Choose fiber counting: all carbs at 4 kcal/g, or fiber at 2 kcal/g.
- Read the total calories and the percent from each macro.
- Compare with the label or copy the summary.
Macros to calories formula
Calories = protein (g) × 4 + carbohydrates (g) × 4 + fat (g) × 9 + alcohol (g) × 7
Macro % = macro calories ÷ total calories × 100
Example: 150 g protein, 200 g carbs and 65 g fat → 600 + 800 + 585 = 1,985 kcal; split 30% protein, 40% carbs, 29% fat.
Calories per gram reference
| Nutrient | kcal per gram | kJ per gram | 10 g equals |
|---|---|---|---|
| Protein | 4 | 17 | 40 kcal |
| Carbohydrate | 4 | 17 | 40 kcal |
| Fat | 9 | 37 | 90 kcal |
| Alcohol (ethanol) | 7 | 29 | 70 kcal |
| Dietary fiber | 2 | 8 | 20 kcal |
| Polyols (most sugar alcohols, EU) | 2.4 | 10 | 24 kcal |
These general Atwater factors are used on nutrition labels worldwide. Actual energy absorbed varies slightly between foods.
Frequently asked questions
How many calories are in a gram of protein, carbs and fat?
Using the standard Atwater factors: protein 4 kcal per gram, carbohydrates 4 kcal per gram, fat 9 kcal per gram and alcohol 7 kcal per gram. Dietary fiber provides about 2 kcal per gram.
How do I convert macros to calories?
Multiply each macro by its factor and add them up: calories = protein g × 4 + carbs g × 4 + fat g × 9 (+ alcohol g × 7). For 30 g protein, 45 g carbs and 15 g fat: 120 + 180 + 135 = 435 kcal.
How do I calculate macro percentages?
Divide each macro's calories by the total calories and multiply by 100. In the example above, protein is 120 ÷ 435 = 27.6%, carbs 41.4% and fat 31.0%.
Why doesn't my total match the nutrition label?
Labels round grams and calories, may count fiber at 2 kcal/g or not at all, and sugar alcohols at lower values. Differences of 5–10% are common and normal.
Is fiber counted in calories?
In the US, fiber is part of total carbohydrates and many labels count it at 4 kcal/g. EU and UK labels count fiber at 2 kcal/g. Choose the fiber option to match the label you are checking.
What is a good macro split?
The US Dietary Guidelines' acceptable ranges for adults are 10–35% of calories from protein, 45–65% from carbohydrates and 20–35% from fat. Athletes and people on specific diets may use different ratios.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.