About TDEE Calculator Kit
Built by a clinical pharmacist to close the gap between peer-reviewed metabolic science and the calorie tools people actually rely on. Every formula is named. Every claim is sourced.
PharmD · MPhilOsama Amir Khan
PharmD · Clinical Pharmacist · MPhil in Pharmacology
Osama Amir Khan holds a PharmD (Doctor of Pharmacy) and an MPhil in Pharmacology, with years of direct patient-facing clinical practice. His daily work involves medication review, patient counselling, and translating clinical evidence into treatment decisions. That same discipline is applied here to caloric science and metabolic nutrition.
He built this site because most calorie tools hide their formulas, ignore clinical context, and rely on anecdotal fitness advice. Every calculator here uses a named, peer-reviewed equation. Every article cites its primary sources.
Make accurate nutrition free for everyone.
Give every person a medically grounded, easy to use tool that shows them exactly how many calories their body needs. No paid plans. No misleading numbers. No supplement upsells.
The science has been published for decades. This site builds the cleanest, most accurate version of it anyone can access for free.
Medically grounded
Built on peer-reviewed equations used in clinical practice today.
Free, forever
No paid plans, no accounts, no supplement upsells. Ever.
Honest numbers
Outputs depend only on your inputs, never on advertisers.
Every Tool on This Site
All 15 calculators are free, ad-free, and built on validated clinical formulas. No account required.
Core Calorie Calculators
Body Composition
Activity and Hydration
The Formulas We Use and Why
Many calculators online never tell you which formula they use. That is a real problem because different formulas produce meaningfully different results.
Mifflin-St Jeor
Our primary formula. Published in 1990 and recommended by registered dietitians in clinical practice today. A 2005 study in the Journal of the American Dietetic Association confirmed it outperforms Harris-Benedict in accuracy across diverse populations.
Harris-Benedict
The original BMR equation, developed in 1919 and revised in 1984. Available as an alternative for comparison. Tends to overestimate slightly, particularly at higher body weights.
Katch-McArdle
Used when body fat percentage is known. More accurate for lean individuals and athletes because it factors in lean body mass directly.
Activity Multipliers
Derived from doubly labeled water studies, the gold standard for measuring real-world energy expenditure. Ranges from 1.2 for sedentary individuals to 1.9 for very high activity levels.
Where Our Information Comes From
Every claim, formula, and recommendation traces back to published research or established clinical guidelines. Primary sources include the American Journal of Clinical Nutrition, Journal of the Academy of Nutrition and Dietetics, Obesity Reviews, WHO dietary reference values, and NIH body weight guidelines.
No sponsored content. No advertiser influences outputs. The numbers produced by any calculator on this site depend only on the inputs you provide and the validated formula applied. Advertising revenue does not exist here because this site carries no advertising.
Why You Can Trust These Numbers
Six things that separate this site from generic calorie calculators.
PharmD and MPhil credentials
Osama Amir Khan holds a PharmD (Doctor of Pharmacy) and an MPhil in Pharmacology with years of patient-facing clinical experience. This is not a fitness blogger running numbers through a spreadsheet.
Formula transparency
Every calculator tells you exactly which equation it uses and why. You can verify the formula yourself in any pharmacology or nutrition textbook.
No financial conflicts
This site does not sell supplements, coaching services, or meal plans. There are no affiliate deals with product companies.
Safe recommendations
Deficit targets stay within clinically safe ranges. The site flags when calorie levels drop below thresholds that could cause harm.
Regular updates
When new research changes best practice, the content is updated to reflect it. Update dates are shown on every article.
Primary sources cited
Articles link to the peer-reviewed research behind their claims, not secondary blog summaries. Readers can verify everything independently.
A Note on Medical Advice
This calculator is an educational tool. It produces estimates based on validated population-level formulas. It does not know your medical history, medications, or any conditions affecting your metabolism.
If you have thyroid disease, PCOS, diabetes, a history of disordered eating, or any metabolic disorder, work with a registered dietitian or your physician before making significant changes to your calorie intake. The numbers here are a starting point, not a prescription.