What are the sources for macro calculations?

Adult AMDR percents are from the National Academies DRI table for macronutrients (Food and Nutrition Board, Dietary Reference Intakes 2002/2005), https://www.nationalacademies.org/cdn/materials/9fb9fae6-337c-4b7c-9821-2c81d1f65ad0. The 4, 4, and 9 kcal per gram factors are the general Atwater factors described by the USDA Agricultural Research Service, https://agresearchmag.ars.usda.gov/2013/sep/calories.

Macro Calculator

Split a calorie intake you already have into protein, carbohydrate, and fat. You pick the percents. An estimate, not a diagnosis.

Calorie intake *

Goal split *

Smart Tips

• Start from a calorie intake you already have. The calorie page estimates that number. This page only splits it.

• The menu shows the percents. 25/45/30 matches the illustration on the calorie page.

• Grams use 4 kcal per gram of protein, 4 per gram of carbohydrate, and 9 per gram of fat.

• A custom split that adds up to 100 is calculated even when it sits outside the adult AMDR. The result says so.

• Protein grams here are a calorie split. The protein page uses body weight instead.

• This is a planning split, not a diet for kidney disease, diabetes, or pregnancy.

The Formula

grams = calories × percent / 100 / kcal per gram

4 kcal per gram of protein
Atwater general factor

4 kcal per gram of carbohydrate
Atwater general factor

9 kcal per gram of fat
Atwater general factor

AMDR Adult ranges
Protein 10–35%, carbohydrate 45–65%, fat 20–35%

The three percents must add to 100. A split outside the adult AMDR is still shown, and the line under the result says it is outside that range.

Key Insights

You pick the split

The calorie page uses one fixed 25/45/30 illustration. Here the percents are a choice you can read before you calculate.

No second TDEE

Calorie intake is an input. This page does not rerun Mifflin–St Jeor or an activity factor.

AMDR is a range

The adult Acceptable Macronutrient Distribution Range is 10–35% protein, 45–65% carbohydrate, and 20–35% fat. It is not one required split.

Link to protein grams

If you want grams from body weight and a g/kg multiplier, use the protein calculator. Do not treat these two pages as the same sum.

Medical Disclaimer

Estimate only: This page is an estimate, not a diagnosis, a lab test, or a treatment plan.

Not a prescribed diet: A split outside the adult AMDR is labeled, not blocked. Kidney disease, diabetes, and pregnancy need a clinician, not this form.

Frequently Asked Questions

The calorie calculator already estimates BMR, TDEE, and a target. This page only turns a calorie number into grams. Enter the intake you want to split.

Each preset prints its percents: 25/45/30, 30/45/25, and 15/55/30. All three sit inside the adult AMDR. 25/45/30 is the same illustration the calorie page uses. None of them is a required diet.

Protein grams are calorie intake times the protein percent, divided by 4. Carbohydrate uses 4 as well. Fat uses 9. Those are the general Atwater factors.

If they add to 100, the page still returns grams and says the split is outside the adult AMDR. The adult ranges are protein 10–35%, carbohydrate 45–65%, and fat 20–35% of energy.

This page splits calories. The protein page multiplies body weight by a grams-per-kilogram figure you can see. Use both if you want to compare the two, and do not expect them to match.

Adult AMDR percents are from the National Academies DRI table for macronutrients (Food and Nutrition Board, Dietary Reference Intakes 2002/2005), DRI Acceptable Macronutrient Distribution Ranges. The 4, 4, and 9 kcal per gram factors are the general Atwater factors described by the USDA Agricultural Research Service, An Improved Method To Estimate Calories.

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Protein

Enter values to calculate

Carbohydrate

Fat

Note:Grams use 4, 4, and 9 kcal per gram. The split is the one you picked. This is an estimate, not a diagnosis or a prescribed diet, and it does not estimate calorie needs.