How We Build Tools

How We Build Tools

This page describes the method behind every calculator on Tidy Moss: where the numbers come from, how calculations are structured, and what their limits are.

1. Formula first

Every tool is built around a published or standard calculation method, and that method is printed on the tool page itself — the formula, the inputs it expects, and a worked example. If a page cannot explain its own arithmetic, the tool does not ship.

2. Reference data with named sources

Values used by the tools come from public, citable sources rather than invented figures:

  • Nutrient values (calories, carbohydrate, protein, fat, fiber, sodium, potassium, vitamins): reference values per 100 g from the USDA FoodData Central database and the Daily Values used on U.S. nutrition labels.
  • Activity energy expenditure: MET (metabolic equivalent) values informed by the Compendium of Physical Activities, applied as calories = MET × body weight (kg) × time (hours).
  • Unit relationships: definitions fixed by international agreement (for example, one pound is exactly 0.45359237 kilograms; one stone is exactly 14 pounds).
  • Dietary reference figures (such as sodium or potassium targets): the Dietary Guidelines for Americans and comparable public guidance.

3. Calculation conventions

Per-100 g food values are scaled by serving weight (grams ÷ 100 × per-100 g value). Where a tool reports "net carbs", that means total carbohydrate minus dietary fiber, and the page says so. Where rounding applies, the rounding rule is stated. Conversions between pounds and kilograms use the exact published factor.

4. Stated limitations

Nutrient values are averages: actual composition varies with growing conditions, harvest, storage, brand, and preparation. MET values describe typical intensities, not individual sessions — age, sex, muscle mass, pacing, and effort all shift the real number. Pages state these limits instead of implying laboratory-grade precision.

5. Review cadence and corrections

Reference data is reviewed periodically against its published sources, and every tool page carries a last-updated date. Corrections reported through the contact page are checked against the underlying source before the page is changed.

6. Independence

All tools are built in-house; none are embeds or iframes of third-party calculators. Tool pages link to the public sources they rely on so that every figure can be traced and verified.

Last updated: October 24, 2026