This calculator splits your daily calories into grams of protein, carbohydrates and fat. Enter your body measurements for an estimate, or use a calorie number you already have.
How it’s calculated
Choose a split, then multiply your calories by each macro’s share and divide by its calories per gram:
Grams = daily calories × share ÷ calories per gram
According to the USDA, carbohydrates and protein provide 4 calories per gram, and fat provides 9.
Worked example
2,000 calories a day with the balanced split of 25% protein, 45% carbohydrates and 30% fat:
- Protein: 2,000 × 0.25 = 500 calories, and 500 ÷ 4 = 125 grams.
- Carbohydrates: 2,000 × 0.45 = 900 calories, and 900 ÷ 4 = 225 grams.
- Fat: 2,000 × 0.30 = 600 calories, and 600 ÷ 9 = 66.7, which rounds to 67 grams.
125 g of protein, 225 g of carbohydrates and 67 g of fat a day.
The splits and the adult ranges
Adult ranges are the Acceptable Macronutrient Distribution Ranges in the Dietary Guidelines for
Americans, 2020–2025, for adults aged 19 and over.
Where the calories come from
If you choose “Estimate for me”, the calculator uses the Mifflin-St Jeor equation and your activity level, then adjusts for your goal, exactly as the Calorie Calculator does. See that page for the formula and its limits. If you already have a number from a doctor or dietitian, choose “I know my calories” and use theirs.
Common questions
Which macro split should I choose?
There's no single right answer, and all three splits here stay inside the adult ranges in the US Dietary Guidelines. The balanced split is a reasonable place to start. Pick the one that suits how you like to eat, and talk to a dietitian if you have a specific goal or a health condition.
How much protein do I need?
MedlinePlus, from the US National Library of Medicine, says healthy adults should get 10% to 35% of their calories from protein, and gives this example. On a 2,000-calorie diet, 100 grams of protein is 400 calories, which is 20% of the total. The splits here range from 20% to 30%.
What about macros for weight loss?
This calculator handles it through your calorie target. Choose the weight loss goal or enter a lower calorie number, and the grams will follow. This calculator doesn't offer very low-calorie targets, and it shows a warning if your number is very low or if your BMI is already below 18.5.
Why can't I choose a keto or very low-carb split?
Because those fall outside the adult ranges that we use as the basis for this calculator, where carbohydrates are 45% to 65% of calories. If you are following one of those diets, ideally with professional guidance, your dietitian's numbers should come first.
Does alcohol count?
It has calories but isn't one of the three macros here, so this calculator doesn't track it. If you drink, those calories come on top of what you see in the table.
Why do fat grams look so low?
Fat has more than twice the calories per gram of protein or carbohydrates, 9 compared with 4. The same 30% of your calories gives far fewer grams of fat than of carbohydrates at 45%.