About Smart Decking Calculator

What this site is

Smart Decking Calculator is a free set of deck planning tools — currently more than seventy of them — covering everything from a whole-project cost estimate down to baluster spacing and ledger fastener layout. There is no sign-in, no email gate and no paywall on any of it.

It exists because deck pricing is opaque in both directions. Homeowners get a quote with a single number on it and no way to judge whether it is reasonable. Contractors lose work because the customer has no frame of reference for why a composite deck four feet off the ground costs what it does. Showing the arithmetic helps both.

Where the numbers come from, and what they are not

Two kinds of number appear on this site, and they have very different standing.

Code and engineering figures are sourced. Joist and beam span tables, ledger fastener spacing, stair rise and run limits, throat depth minimums and guard requirements come from the American Wood Council's DCA 6 prescriptive residential deck guide and the model residential code it is written against. Where a page quotes one of these, it says which table it is from so you can check it. These are not estimates.

Cost figures are estimates, and are labelled as such. They are national average ranges compiled from published supplier and manufacturer pricing and public remodelling cost data, adjusted for region. They are a starting point for judging a quote, not a quote. Local lumber prices, how busy builders are in your area, site access and what the tear-off reveals all move the real number, sometimes by a lot. Every cost calculator on the site states its assumptions on the page rather than burying them.

What we do not do is claim a precision the method cannot support. There is no proprietary database of contractor quotes behind these figures and no survey panel — just published ranges, arithmetic you can follow, and assumptions written down.

How the tools are built

Each calculator is a pure function: the same inputs always produce the same output, and the working is shown in the breakdown beneath the result rather than hidden. Where a calculation is governed by a code table, the table is encoded directly and the page names it. Where a result would fail a code limit — a riser over 7¾ inches, a joist span past what the species allows, a stringer throat under 5 inches — the tool says so rather than quietly returning a number.

Nothing on this site is a substitute for your local building department. Codes are adopted and amended locally, frost depths vary by county, and an inspector's interpretation is the one that counts. Use these tools to plan and to check, then confirm before you build.

Corrections

If a figure here looks wrong, it might be. Tell us on the contact page with the page and the number, and it gets checked and fixed rather than argued about.

Sister calculators

Planning a wider exterior project? The same approach applied to two other trades: Smart Roofing Calculator and Smart Fencing Calculator.

Who runs it and how it is funded

Smart Decking Calculator is owned and operated by DixonAppStudio LLC, a small independent software studio in Elgin, South Carolina, USA. The calculators are free; the site is supported by Google AdSense ads, kept separate from the tools, and by Amazon affiliate links (see the affiliate disclosure and privacy policy). Questions or corrections: support@dixonappstudio.com or the contact page.

Android apps

For working on site without a signal, the calculators are also on Google Play: Smart Decking Calculator, Smart Fencing Calculator and Smart Drywall Calculator.