How we calculate

MeretAI documents how each calculator works so results stay transparent. This page is the site-wide overview. Every tool page also lists its own formula, assumptions, and a worked example.

Formulas

Each calculator page documents its formula in plain text, lists assumptions, and includes a hand-checked worked example. Math runs with deterministic JavaScript (no eval, no AI APIs). Rounding is shown on the page when it matters (for example money rounds to the cent).

What we do not cover

These tools are planning aids. They do not replace product labels, local building codes, veterinary advice, institutional grading rules, or professional engineering. Where a number depends on a brand or a supplier (paint coverage, mulch bag size, gravel density), you can override the default.

Testing

Golden fixtures ship with each tool. A Node test runner checks inputs against expected outputs within a tolerance. When we change a formula, we update the fixtures and the worked example on the page.

Rounding

Display rounding is for readability. Use the raw formula if you need more precision for accounting, grades, or material orders. Money tools typically round up to the cent so a bill is covered.

Updates

When a formula or assumption changes, we update the tool page, the fixtures, and the last-updated date on that tool. Prefer correctness over shipping stubs.

Sources

Where a standard conversion factor is used (for example the unit converter), we prefer well-known SI relationships. Product coverage numbers (paint gallons, mulch bags) come from common DIY defaults that you can override.