Nutrition calculators that show every formula they run
Nine calculators for energy, macros, and body composition — each one names its equation, its source, the assumptions baked into it, and the population it was built on. No black boxes, no hidden multipliers, no "trust us."
- 100% free, no sign-up
- Runs in your browser — no data leaves your device
- Equation, version, and source shown per tool
Calculators
TDEE Calculator
Daily energy expenditure — Mifflin × activity levels with a second NASEM 2023 reading.
Calorie Calculator
Intake targets for cutting, maintaining, or bulking, with optional zigzag high/low days.
BMR Calculator
Resting metabolism three ways — Mifflin, Harris–Benedict, and Katch–McArdle side by side.
Macro Calculator
Protein, fat, and carb grams from your calories, with presets and a custom split.
Protein Calculator
Grams per kilogram from the 0.8 g/kg RDA up to the 2.0 g/kg ISSN range.
Carb Calculator
The 45–65% AMDR range translated into daily grams, with a fiber note.
Calorie Deficit Calculator
Deficit sizes, expected weekly loss, and an honest note on metabolic adaptation.
Body Fat Calculator
US Navy tape method — body fat %, fat mass, and fat-free mass for the Katch–McArdle BMR.
BMI Calculator
WHO eight-level classification plus BMI Prime and the Ponderal index.
Guides
Four TDEE Formulas, One Honest Comparison
Four TDEE equations compared honestly: what each assumes, who each was validated on, and where each one drifts.
Calibrating Your TDEE: Trust the Calculator First, the Scale Last
Replace equation estimates with your own number: a four-week self-calibration protocol using weight trend and intake records.
Metabolic Adaptation, Honestly Sized
Why predicted weight loss outruns real results: adaptive thermogenesis, the 7700 kcal rule’s limits, and Hall 2011’s modeling.
Why every result links to its math
Most calculator sites hide the equation behind the result, so you can never tell whether a difference between two tools is a different formula or a bug. Here the equation, its published version, the source it comes from, and the population it applies to travel with every number you get. When a method is rough — and the activity multipliers genuinely are a rough mapping, not a validated model — the page says so where you can see it.
All nine calculators run entirely in your browser. Height, weight, age, and tape measurements never enter a URL, never touch a server, and work with JavaScript disabled (as static explanation pages).
About this site
- How we calculate — The four-state formula transparency standard and the parameter–source registry.
- Sources & update log — Every equation version, every source change, dated and logged.
- Who builds these tools — One named developer, the review policy, and how corrections are handled.