How we calculate & our sources

Every calculator is built to be transparent and checkable. Here's how:

• We name our sources. Where a tool rests on a code or standard, it names the specific code and edition (e.g. National Plumbing Code of Canada 2020, IPC 2021) so you can verify it at the source. Pure-math tools — volumes, conversions, geometry — show the standard formula they use instead.
• We use published model codes and engineering references. Values are derived from the governing code tables and standard formulas — not invented.
• We write in plain English. We paraphrase requirements in our own words and cite the clause; we don't reproduce copyrighted code text.
• We show units for your region. Metric or imperial, matched to where you are, with a toggle.
• We date our reviews. Pages show when they were last reviewed and which code edition they reflect.

Codes are adopted and amended locally and change over time. Our results are a fast, transparent indication for typical work — they don't replace your local Authority Having Jurisdiction (AHJ) or a licensed professional.