Updated
Methodology: where our numbers come from
This page explains the formulas behind our calculators, where the food and activity data comes from, how we keep it current and what our estimates do not cover. It is the site's editorial charter.
Formulas
- BMR: Mifflin-St Jeor equation (1990), with Harris-Benedict as a reference.
- TDEE: BMR multiplied by an activity factor from 1.2 (sedentary) to 1.9 (extremely active).
- BMI: World Health Organization classification.
- Calories burned: MET values from the Compendium of Physical Activities (Ainsworth et al.).
- Macros: 4 kcal per gram of protein and carbohydrate, 9 kcal per gram of fat; protein ranges from International Society of Sports Nutrition guidance.
Data
Food nutrition values come from USDA FoodData Central; activity intensities from the Compendium of Physical Activities.
Updates
Formulas and data are reviewed when the reference sources publish new values. Every page shows, at the top and at the bottom, the date of its last real change.
Limits
Results are estimates for guidance only. Individual metabolism varies, and our calculators do not replace advice from a doctor or a registered dietitian, especially during pregnancy, for children, or with a medical condition.
Report an error
Does a figure look wrong? Write to contact@calorierule.com with the page and your source. We check every report and correct the page, whose update date then changes.
See also about the author.