Editorial policy

Free Deck Board Calculator publishes free deck calculators and practical guides. This page explains where our information comes from and how we keep it accurate.

Sources we use

• Building codes: the International Residential Code (IRC), especially the deck provisions in R507 and the stair and guard sections R311 and R312, plus official county deck guides that reproduce the IRC tables.
• Industry references: the American Wood Council's deck construction guide (DCA 6) and preservative-treatment standards.
• Manufacturer instructions: published installation guides for decking, fasteners and railings. Brand names are used only to reference these documents; we're not affiliated with any manufacturer or retailer.
• Cost data: published cost guides, always shown as ranges with the year and source. We never present prices as live or local.

Specific figures — a code limit, a gap spec, a price range — link to the source where they appear.

How the calculators are checked

• Every formula lives in tested code. Automated tests cover normal decks, edge cases (zero, negative, empty and extreme values), metric conversion and every feature, and must pass before a change goes live.
• Worked examples in our articles are computed by the same code at build time, so the numbers in the text always match the tools.
• The calculation method and its assumptions are documented on the about page.

What we don't do

• We don't give structural engineering advice. Calculators that touch framing, footings, stairs or railings count materials only and point to the code tables.
• We don't publish fake reviews, invented statistics or sponsored rankings.
• Advertising never influences which materials or methods we describe.

Updates and corrections

We review content when codes or manufacturer instructions change, and every guide shows the date it was last updated. If you spot an error, please contact us — corrections are made promptly and the update date changes.