How this calculator works
The adult Acceptable Macronutrient Distribution Range is 20 to 35% of total energy for fat. General Atwater energy factors convert that share to grams. You may enter an energy budget or estimate it with the current adult EER model. A chosen share outside the range is displayed with a note, rather than treated as a diagnosis. The result is an estimate for information only and is not medical advice.
Formula
Fat grams = daily kcal x energy fraction / 9. Reverse: daily kcal = grams x 9 / fraction. Ranges apply to healthy adults aged 19 and older.
Worked example
At 1800 kcal/day the adult fat range is 40 to 70 g. A 30% share gives 60 g.
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Frequently asked questions
Is the chosen share a prescription?
No. It is an arithmetic allocation, and food quality and medical needs still matter.
Why is there a range?
The DRI range allows different eating patterns while supporting nutrient adequacy.
Can I use the adult range for a young child?
No. Children have different fat and protein ranges; use the DRI calculator for age-specific reference information.