How to Count Macros, With the 4, 4, 9 Math Explained
By Eric Parker, founder of TrueCal. Published . Sources checked .
Written with AI assistance from the cited studies. Every claim was checked against its source. Editorial policy.
Key takeaways
- Protein and carbohydrate carry about 4 calories per gram, fat about 9 and alcohol about 7.1
- The National Academies' ranges are 45 to 65 percent of calories from carbohydrate, 20 to 35 percent from fat and 10 to 35 percent from protein.34
- For people who exercise, the International Society of Sports Nutrition puts protein at 1.4 to 2.0 grams per kilogram of body weight a day, in doses of about 20 to 40 grams.6
- Label calories won't always match your 4, 4, 9 math, because of rounding and how makers count fiber and sugar alcohols.2
How do you count macros?
Counting macros means logging the grams of protein, carbohydrate and fat you eat each day, and knowing what those grams are worth in calories. Protein and carbohydrate give about 4 calories per gram and fat about 9. These are the general factors in FAO's 2003 report on food energy, and the same 4, 4 and 9 appear in FDA labeling rules.12
Alcohol is a fourth source of calories, at about 7 per gram. FAO also recommends about 2 calories per gram for dietary fiber.1
How to turn grams into calories
Multiply each macro's grams by its factor, then add them up. FAO notes that the Atwater system spread partly because it's so simple. Factors worked out for single foods differ a little from the general ones, which is one reason your math won't match every label exactly.1
- Multiply grams of protein by 4.
- Multiply grams of carbohydrate by 4.
- Multiply grams of fat by 9.
- Add the three together for the calories in the food.
What macro ranges should you start from?
The National Academies' 2005 Dietary Reference Intakes set Acceptable Macronutrient Distribution Ranges, or AMDRs, as a share of calories. They are 45 to 65 percent from carbohydrate, 20 to 35 percent from fat and 10 to 35 percent from protein. On a 2,000 calorie day, that works out to the grams in the table.34
Any split inside those ranges is a reasonable place to start. Pick one, log for a couple of weeks, and adjust from how you feel and what your log shows.
How much protein should you count toward?
Protein also has a per-weight number. The RDA is 0.8 grams per kilogram of body weight a day. Wolfe's 2017 review points out that the low end of the protein AMDR is higher than the RDA, so the two give different answers for the same person.5
For people who exercise, the International Society of Sports Nutrition's 2017 position stand says 1.4 to 2.0 grams per kilogram a day is enough for most. It suggests spreading protein across the day in doses of about 20 to 40 grams, or 0.25 grams per kilogram, every 3 to 4 hours.6
If you're eating less to lose weight, the protein guide covers what studies found about protein during a calorie deficit.
How to set your macro targets
- Start with your daily calories. A TDEE calculator gives a first estimate.
- Set protein in grams from your body weight.
- Choose a fat share inside its range, and turn it into grams by dividing those calories by 9.
- Give the calories left over to carbohydrate, divided by 4.
- Check that protein, fat and carbohydrate add back up to your calorie number.
How to count macros day to day
TrueCal Pro shows protein, carbohydrate and fat for each meal you log. Type what you ate in plain words and the macros fill in, so the steps below are mostly checks.
- Log every food with an amount, the same way you'd log calories.
- For packaged food, take protein, carbs and fat from the label and multiply by the servings you ate.
- For whole foods, use an entry that matches how you weighed the food, raw or cooked.
- Check the day's totals once, at the end of the day, rather than after every meal.
- Look at weekly averages as well as single days.
Why your macros don't match the label
Rounding is part of it. On a label, calories round to the nearest 5 up to 50 and the nearest 10 above that. Protein and carbohydrate round to the nearest gram, and fat to the nearest half gram below 5 grams.2
Method is the rest. Besides plain 4, 4 and 9, makers may give sugar alcohols their own factors, or use factors worked out for that food, or measure calories in a lab.2
When the two disagree by a few calories, log the label's calories and its grams as printed.
Worked example
Say a lunch has 30 grams of protein, 45 grams of carbohydrate and 15 grams of fat. That's 30 times 4, or 120 calories from protein, 45 times 4, or 180 from carbohydrate, and 15 times 9, or 135 from fat, for 435 calories in all. Protein is 120 of the 435, about 28 percent of the meal's calories.1
A closer look
A label's calories won't always equal 4, 4 and 9 times its grams, and that's allowed. FDA rules let makers subtract non-digestible carbohydrates and sugar alcohols from carbohydrate before multiplying, count soluble non-digestible carbohydrate at 2 calories a gram, and round calories to the nearest 5 or 10, so a small gap between your math and the label is expected, not an error.2
Questions and answers
Should I subtract fiber from carbs?
On a US label, total carbohydrate includes fiber, and makers may subtract non-digestible carbohydrates before working out calories. FAO gives fiber about 2 calories per gram. For counting, log total carbohydrate as the label lists it, and track fiber as its own number if you want it.21
What's the difference between the RDA and the AMDR for protein?
The RDA is 0.8 grams per kilogram of body weight a day. The AMDR is 10 to 35 percent of calories. Wolfe's 2017 review notes that the low end of the AMDR is higher than the RDA.5
How much protein should be in each meal?
For people who exercise, the ISSN position stand suggests about 20 to 40 grams, or 0.25 grams per kilogram, every 3 to 4 hours.6
Do I need to count macros or just calories?
Calories alone tell you about energy. Macros add detail on protein, carbs and fat, which helps if you have a protein goal or train for a sport.
Count macros with TrueCal
TrueCal Pro turns a meal you type in plain words into calories, protein, carbs and fat, so the math is done as you log.
Get TrueCal on the App Store Get TrueCal on Google PlaySources
- Food Energy, Methods of Analysis and Conversion Factors. FAO. 2003.
- 21 CFR 101.9, Nutrition Labeling of Food. FDA. 2026.
- Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Institute of Medicine. 2005.
- Current Sports Medicine Reports. Manore. 2005.
- Advances in Nutrition. Wolfe. 2017.
- Journal of the International Society of Sports Nutrition. Jäger. 2017.