Plateknow A macro split is a share of your calories. This turns those shares into grams, shows the published band each one normally sits inside, and tells you when yours is outside it — without changing it for you.
That is the target. The hard part is the other half — knowing what you actually ate.
Download freeThe bands, and where they come from
| Macronutrient | Published band | Energy per gram |
|---|---|---|
| Protein | 10–35% of calories | 4 kcal |
| Fat | 20–35% | 9 kcal |
| Carbohydrate | 45–65% | 4 kcal |
These are the Acceptable Macronutrient Distribution Ranges from the Dietary Reference Intakes (Institute of Medicine, 2005). They are wide on purpose: inside them, the evidence does not favour one split strongly enough to name one. The calculator’s default of 20 / 30 / 50 is the middle of all three, and it is not a recommendation.
Why it flags a split instead of fixing it
A low-carbohydrate split sits outside the published band, and it is also something a great many people are doing deliberately and with advice. Both of those are true at once. So the calculator says which one is outside the band and then leaves it alone — an app that silently rewrote your input would be doing the exact thing this site says it will not do.
The arithmetic is not the hard part
Percentages to grams is one division. Going from grams to a plate is the difficulty, and it is why macro calculator for food and macro calculator for recipes are both live autocomplete on this term. People are not asking to divide; they are asking what is in the thing they are about to eat.
A photograph will not read a macro split off a plate exactly — nothing will — but it will tell you roughly where the grams went, which is more than a percentage does.
Do the three have to add up to 100?
Yes — they are shares of the same calories, so anything else is describing a different day’s eating. The calculator waits for 100 rather than quietly adjusting one of them.
Where does the calorie number come from?
From the calorie calculator on this site, which works it out from your weight, height, age and how much you move. It is linked at the bottom of this page. Any other source works too — the split does not care where the total came from.
What about fibre and sugar?
Fibre is a carbohydrate and is counted inside the carbohydrate share, which is why the result shows it separately at 14 g per 1,000 calories. Added sugars are also inside it, and they carry their own FDA Daily Value of 50 g on a 2,000-calorie reference.
Is PFC the same thing as macros?
Yes. Protein, fat, carbohydrate — PFC is the usual name in Japan, and PFCバランス is the search term there. Same three numbers, same arithmetic.
Institute of Medicine, Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) — Acceptable Macronutrient Distribution Ranges, and the fibre Adequate Intake of 14 g per 1,000 kcal. FDA, Daily Values on the Nutrition and Supplement Facts labels — added sugars 50 g on a 2,000-calorie reference.