How Kaloria's calculators work
Last updated: 27 October 2026
Every calculator on kaloria.ai uses a published equation or reference value, and runs in your browser. This page lists the formulas, where they come from and where they stop being accurate.
Not medical advice. The results are population averages for healthy adults. They are not a diagnosis or a treatment plan. If you are pregnant or breastfeeding, have a medical condition (for example diabetes, a thyroid or kidney disease or an eating disorder), or take weight-loss medication, follow your doctor's or a registered dietitian's advice instead.
Formulas we use
| Calculator | Method | Source |
|---|---|---|
| Daily energy (BMR / TDEE) | Mifflin–St Jeor equation for resting energy, multiplied by a physical activity level (about 1.2–1.9). Where you enter body fat, the Katch–McArdle equation (based on lean mass) is used instead. | Mifflin 1990; FAO/WHO/UNU 2004 |
| Weight change and timelines | About 7,700 kcal per kg of body weight, used as a first approximation. Real loss slows over time as energy needs fall, so long timelines are optimistic. | Hall 2008 |
| Pregnancy | Pre-pregnancy energy needs plus about +340 kcal/day in the second trimester and +452 kcal/day in the third; no extra energy in the first trimester. | IOM 2005 |
| Breastfeeding | About +330 kcal/day in months 0–6 and +400 kcal/day in months 7–12 of exclusive breastfeeding (European reference: about +500 kcal/day). | IOM 2005; EFSA 2013 |
| Cutting, bulking, body recomposition | Your estimated maintenance energy with a chosen deficit or surplus, and protein targets per kg of body weight. | Mifflin 1990; FAO/WHO/UNU 2004 |
| Life expectancy | A national life-table baseline for your age and sex, adjusted by rough averages for smoking, alcohol, activity, body weight, diet and sleep. It is an illustration of how habits relate to longevity, not a prediction for you. | National life tables (e.g. CDC, MHLW Japan) |
| Sleep | Bed and wake times in multiples of an average ~90-minute sleep cycle, plus about 15 minutes to fall asleep. Real cycles vary between people and through the night. | General sleep-physiology convention |
Known limits
- Prediction equations are typically within about ±10 % of measured resting energy for most adults, and can be further off for very lean, very muscular or older people.
- Activity levels are self-reported and are the biggest source of error; track your weight for 2–3 weeks and adjust.
- Translated calculators use the same formulas in every language. Where a country publishes its own reference values, the page should say so; tell us if you find one that doesn't.
Who writes and checks these pages
The calculators and their explanations are written and maintained by the Kaloria team (see about us). They are not reviewed by a licensed clinician. We check each formula against its source, and we correct errors as soon as we learn about them: write to info@kaloria.ai.
Sources
- Mifflin MD, St Jeor ST et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51:241–247. pubmed.ncbi.nlm.nih.gov
- FAO/WHO/UNU. Human energy requirements. Report of a Joint Expert Consultation, Rome 2004 (physical activity levels). www.fao.org
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005 (pregnancy and lactation energy). nap.nationalacademies.org
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for energy. EFSA Journal 2013;11(1):3005. www.efsa.europa.eu
- Hall KD. What is the required energy deficit per unit weight loss? Int J Obes 2008;32:573–576. pubmed.ncbi.nlm.nih.gov
- U.S. CDC, National Center for Health Statistics. United States life tables. www.cdc.gov
- Ministry of Health, Labour and Welfare (Japan). Abridged life tables (簡易生命表). www.mhlw.go.jp