Carb Calculator

This calculator estimates a reference range, not an individual recommendation. It uses the Mifflin equation to estimate resting energy, then applies one of five calculator scenario multipliers (1.2, 1.375, 1.55, 1.725, or 1.9). The multiplier labels do not claim that an exercise frequency validates a multiplier.

Method and limits

US inputs are converted with 0.453592 kg/lb and 2.54 cm/in. The selected sex branch uses the Mifflin equation:

$RMR=10w+6.25h-5a+5\text{ (male)}$ $RMR=10w+6.25h-5a-161\text{ (female)}$

The calculator rounds RMR × scenario multiplier to obtain an estimated calorie scenario. It converts 45–65% of that scenario to grams at 4 kcal/g. The lower result cannot fall below the adult carbohydrate RDA of 130 g/day.

$\text{lower}=\max\left(130,\operatorname{round}(\text{scenario calories}\times0.45/4)\right)$ $\text{upper}=\operatorname{round}(\text{scenario calories}\times0.65/4)$

The 45–65% adult AMDR and 130 g/day adult RDA are DRI references for generally healthy populations. They do not validate the calorie scenario or establish an individual need. The calculator accepts ages 19–78, matching the age range reported for the Mifflin derivation sample, and should not be used as a clinical diet prescription.

Example

For a 30-year-old male row at 75 kg and 178 cm, the resting estimate is 1,717.5 kcal. The 1.55 scenario gives 2,662 kcal after rounding, and the displayed reference range is 299–433 g/day.

Sources

• National Academies, Acceptable Macronutrient Distribution Ranges — adult carbohydrate AMDR cell, 45–65% of energy; 2002/2005 macronutrient report reference table.
• National Academies, Dietary Reference Intakes macronutrient table — adult carbohydrate RDA, 130 g/day.
• Mifflin et al., resting energy equation — equation population and limits apply; activity multipliers are separate calculator assumptions.