Macro Calculator
This macro calculator splits your daily calories into protein, carbs and fat in about a minute.
Your numbers
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Field Notes that go deeper
The science behind the macro calculator
Show the formulas, method and sources
Macros are the three nutrients that supply calories: protein, carbohydrate and fat. The tool starts from your daily calorie target. Then it divides those calories with a split that stays inside the ranges set for adults.
Formulas
Calories per gram (Atwater general factors)
Protein: 4 kcal/gCarbohydrate: 4 kcal/gFat: 9 kcal/g
Grams per macro
Grams = daily calories x share of calories / calories per gram
Splits offered (protein / carbs / fat)
Balanced: 20% / 50% / 30%Higher protein: 30% / 45% / 25%Higher carb: 20% / 55% / 25%
Acceptable ranges for adults (share of calories)
Protein: 10 to 35%Carbohydrate: 45 to 65%Fat: 20 to 35%
How it works, step by step
- First, the calculator finds your calorie target with the same steps as the calorie calculator.
- Then it multiplies that target by each share in the split you chose.
- Next, it divides each result by the calories in one gram of that macro.
- Finally, it rounds each amount to the nearest whole gram.
Worked example
At 2,000 calories on the Balanced split, protein gets 400 calories, which makes 100 grams. Carbs get 1,000 calories, which makes 250 grams. Fat gets 600 calories, which makes about 67 grams.
Accuracy and limits
The factors of 4, 4 and 9 calories per gram are general averages from an FAO technical workshop. Real foods vary a little around them.
All three splits sit inside the acceptable macronutrient distribution ranges from the Institute of Medicine. The Institute tied those ranges to lower chronic disease risk while still meeting nutrient needs.
Because the protein share counts calories, the grams depend on your target. You can check it against the protein calculator, which works from body weight.
- These are daily averages, so you do not need to hit them exactly at every meal.
- The tool does not build splits outside the ranges above, such as very low-carb plans.
- If you have diabetes, kidney disease or another condition, ask your care team for macro targets.
Sources
- Institute of Medicine. Dietary Reference Intakes: macronutrients (summary table from Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids). National Academies Press; 2005. Used for: Acceptable macronutrient distribution ranges for adults.
- Wolfe RR, Cifelli AM, Kostas G, Kim IY. Optimizing protein intake in adults: interpretation and application of the Recommended Dietary Allowance compared with the Acceptable Macronutrient Distribution Range. Adv Nutr. 2017;8(2):266-275. Used for: The 0.8 g/kg protein RDA and the 10 to 35% protein range.
- FAO. Food energy: methods of analysis and conversion factors. FAO Food and Nutrition Paper 77. Rome; 2003 (chapter 3, energy conversion factors). Used for: The general factors of 4, 9 and 4 kcal per gram for protein, fat and carbohydrate.
Sources and math last reviewed: .
Questions people ask
What are macros?
Macros, short for macronutrients, are protein, carbohydrate and fat. They supply your calories. Each gram of protein or carbohydrate gives 4 calories, while each gram of fat gives 9.
Which split should a beginner pick?
Balanced is a sensible default. If you lift and want more protein, pick Higher protein. When you do long or frequent workouts, Higher carb leaves more room for fuel. You can switch at any time and compare.
How should I set macros for a desk job?
The calculator handles your day through the activity level, so choose the lower level if you sit most of the day. After that, the split decides how those calories divide. A plate with a protein food, a starchy food and vegetables makes an easy way to hit it.
Do I have to hit my macros exactly?
No. They are estimates built on estimates. If you land near them on most days, you are doing fine, and a small miss breaks nothing. Look at your weekly average instead of any single day.
Why is there no keto or very low-carb option?
Every split here keeps carbohydrate at 45% of calories or more, which sits inside the range used for adults. A very low-carb plan falls outside it. If you are considering one, plan it with a clinician or dietitian.
These calculators give general estimates for adults and are not medical advice. For decisions about your own health, talk with a doctor or a registered dietitian. How we write and check things