Sources & Further Reading
Every formula on this site is named and displayed as an equation, so you can check the arithmetic yourself. The primary references behind the calculator are:
- Mifflin MD, St Jeor ST, Hill LA, et al. "A new predictive equation for resting energy expenditure in healthy individuals." Am J Clin Nutr. 1990;51(2):241-247.
- Harris JA, Benedict FG. A Biometric Study of Basal Metabolism in Man. Carnegie Institution of Washington, 1919 (revised by Roza AM, Shizgal HM. Am J Clin Nutr. 1984;40(1):168-182).
- Katch FI, McArdle WD. Nutrition, Weight Control, and Exercise. Lea & Febiger, 1983.
- Frankenfield D, Roth-Yousey L, Compher C. "Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review." J Am Diet Assoc. 2005;105(5):775-789.
- Helms ER, Aragon AA, Fitschen PJ. "Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation." J Int Soc Sports Nutr. 2014;11:20.
Activity multipliers follow the widely used Harris-Benedict classifications. Protein targets during a deficit are set high enough to help protect lean mass, in line with recommendations for athletes in an energy deficit (Helms et al., above).
Built on Modern, Accessible Technology
Calorie Professor is built with Astro for performance, TypeScript for reliability, and Vercel's Geist design system for its visual language. We aim to follow WCAG 2.1 AA guidance: a single logical heading order, labelled form controls, keyboard-operable menus, visible focus states, and sufficient color contrast in both light and dark themes.
The interface is available in 13 languages, including right-to-left layout for Arabic. Language and theme preferences are stored locally in your browser and persist across visits.
Maintenance & Feedback
The calculator is maintained and updated as feedback and new research come in. Additions so far include the Katch-McArdle option, the calorie-cycling schedule, dark mode, expanded language coverage, and the optional meal plan generator.
If you spot an error, have a suggestion, or want to help improve a translation,get in touch.