About Calowly
Calowly is a small, independent project. This page explains who builds it, where the numbers on every calculator and food page come from, and how to tell us when something is wrong.
Who we are
Calowly is built by Jeep, an independent developer based in Bangkok. Jeep makes the Calowly AI app, an AI fat loss coach that estimates the calories in a meal from a photo, as well as this website’s free calculators and calorie database.
Calowly is independent and publishes no sponsored content: no brand pays for the calculators, the food pages or their results. You can reach Jeep at support@calowly.com.
How we calculate
Every calculator uses a published formula. The list below is generated from the same configuration the calculators run on, so it always shows what they actually do.
Calculators
TDEE calculator
Based on: Mifflin-St Jeor equation
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. doi:10.1093/ajcn/51.2.241
Calorie deficit calculator
Based on: Mifflin-St Jeor equation
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. doi:10.1093/ajcn/51.2.241
BMR calculator
Based on: Mifflin-St Jeor equation, Katch-McArdle equation
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. doi:10.1093/ajcn/51.2.241
- McArdle WD, Katch FI, Katch VL. Exercise Physiology (Katch-McArdle equation).
Protein calculator
Based on: Dietary Reference Intakes (protein RDA), Dietary Guidelines for Americans, ISSN position stand on protein (Jäger et al.), Morton et al. meta-analysis
- National Academies. Dietary Reference Intakes: RDA for protein, 0.8 g per kg body weight a day.
- Dietary Guidelines for Americans, 2025-2030: protein goal of 1.2-1.6 g per kg body weight a day.
- Jäger R et al. J Int Soc Sports Nutr 2017;14:20.
- Morton RW et al. Br J Sports Med 2018;52:376-84.
Macro calculator
Based on: Mifflin-St Jeor equation, Dietary Reference Intakes (protein RDA), Dietary Guidelines for Americans, ISSN position stand on protein (Jäger et al.), Morton et al. meta-analysis
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. doi:10.1093/ajcn/51.2.241
- National Academies. Dietary Reference Intakes: RDA for protein, 0.8 g per kg body weight a day.
- Dietary Guidelines for Americans, 2025-2030: protein goal of 1.2-1.6 g per kg body weight a day.
- Jäger R et al. J Int Soc Sports Nutr 2017;14:20.
- Morton RW et al. Br J Sports Med 2018;52:376-84.
Body fat calculator
Based on: US Navy circumference method, ACE body fat categories, Normalized FFMI (Kouri et al.)
- Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center, 1984 (Reports 84-11, 84-29).
- American Council on Exercise (ACE): body fat categories.
- Kouri EM et al. Clin J Sport Med 1995;5(4):223-8 (normalized FFMI).
Food data
Nutrition values come from USDA FoodData Central, the public nutrient database of the US Department of Agriculture. We only use records from its SR Legacy and Foundation datasets, and every food page names the record it uses (its FDC ID), so you can look it up yourself.
Values are per 100 g of the food as described on its page, for example roasted chicken breast or a hard-boiled egg without its shell. Calories and minerals are rounded to whole numbers and the other nutrients to one decimal place. When USDA has no value for a nutrient, that row is left out rather than estimated.
Serving sizes are fixed gram weights stored with each food, such as one cup of cooked rice or one large egg without its shell. They are not measured separately: calories and nutrients per serving are worked out from the per-100 g values (value × grams ÷ 100) and rounded, so they always agree with the main figures. Real portions vary, so weigh your food when you need precision. Browse the calorie database.
How we test
Before any page is published, the build checks every calculator against a fixed set of cases with known results. If a single result is off, the build stops and no calculator page is updated.
The food data is checked on every build too: the calories are compared with the protein, fat and carbohydrate values, and any mismatch is flagged for review.
Every calculator and food page shows who wrote it and when its formula, text or data was last reviewed.
Corrections
Found a mistake? Email support@calowly.com with the page and what looks wrong. We check the report against the source, correct the page and update its “last reviewed” date.
Not medical advice
The calculators give estimates for healthy adults aged 18 to 80 and are not medical advice. If you are pregnant or breastfeeding, or have a medical condition or an eating disorder, talk to a doctor or dietitian before changing how you eat.