What are macros?
“Macros” is short for macronutrients. Protein, carbohydrate, and fat are the three energy-providing nutrients most commonly tracked in grams. This calculator divides the daily energy estimate also used by the calorie calculator among those nutrients.
Macro totals do not describe the complete quality of an eating pattern. Foods also provide fiber, vitamins, minerals, essential fatty acids, amino acids, and other components that percentage targets alone cannot evaluate.
How does the macro calculator work?
The calculator estimates resting energy with Mifflin-St Jeor or revised Harris-Benedict, multiplies that value by an activity factor, applies the selected daily goal adjustment, and assigns the final calories to the chosen macro distribution.
Carbohydrate grams = calories × carbohydrate % ÷ 4
Fat grams = calories × fat % ÷ 9
The fiber planning value uses 14 grams per 1,000 calories, a density used in U.S. Dietary Reference Intake guidance.
Macro percentage ranges
The adult Acceptable Macronutrient Distribution Ranges are 45%–65% of calories from carbohydrate, 10%–35% from protein, and 20%–35% from fat. All three built-in presets stay within those ranges.
Custom entries must total exactly 100% and remain inside the adult ranges. Staying inside a range does not guarantee that a split is appropriate for every health condition, sport, or goal.
How to use the macro calculator
- Choose U.S. or metric units.
- Enter age, height, weight, and select the sex coefficient.
- Select a resting-energy equation and typical activity level.
- Choose maintenance, gradual loss, or gradual gain.
- Select a preset distribution or enter custom percentages totaling 100%.
- Select Calculate Macros and review grams, calories, percentages, BMR, and maintenance.
Understanding the result
The large number is the daily calorie estimate after the selected goal adjustment. The three macro gram values are calculated directly from that calorie total and the chosen percentages.
Rounded grams may reproduce a calorie total that differs by a few calories. Actual maintenance needs can also differ from the prediction, so multiweek weight and performance trends provide more information than one calculated value.
Limitations and safety
The tool does not create meals, evaluate protein quality, distinguish types of carbohydrate or fat, or account for allergies, kidney disease, diabetes, gastrointestinal conditions, medication effects, or athletic periodization. For a body-weight-based daily protein range, use the dedicated protein calculator.
If the selected goal falls below estimated BMR, the result shows a warning. Any aggressive plan, persistent symptoms, major weight change, or medical nutrition need should be discussed with a registered dietitian or qualified clinician.
Frequently asked questions about macros
Sources and methodology
Energy and macro calculations are documented with original research and current U.S. guidance.