About LumberMathz.

Why we built this

Building a 16 × 12 pressure-treated deck should not require a spreadsheet, three browser tabs, and a call to your local lumber yard to figure out how many bags of concrete you need. Most online calculators tell you how many boards to buy — and that's it. You still have to figure out joists, footings, concrete, screws, and railing on your own.

LumberMathz fixes that. Every calculator on this site produces a complete bill of materials — the same list you'd hand to a contractor or read off at the lumber yard. No upsells. No email gates. No ads covering the output.

Who it's for

LumberMathz is aimed squarely at the US DIY audience: homeowners building their first deck, experienced builders who want a quick double-check, and weekend warriors who just want to know how many 2×6s to throw in the truck before heading to the store.

The calculators use industry-standard formulas and typical construction practices for residential wood projects. They are not a substitute for engineered drawings, structural calculations, or local building permits — and we say so clearly on every tool page.

What makes these calculators different

• Complete bill of materials. Not just board counts — joists, footings, concrete, screws, and railing.
• Live plan view. A top-down diagram updates as you type, so you can see your deck layout before you buy.
• Print-ready output. One tap copies or prints a clean shopping list you can hand to the lumber yard.
• Transparent math. Every formula is explained in plain English on the same page — no black box.
• Free, always. No signup, no paywalls, no "download our app."

All six calculators are live

Deck, composite deck, stair, railing & baluster, fence, and board foot — each with a complete bill of materials and a plain-English explanation of the math. Browse them all from the home page or the Calculators menu.

A note on accuracy

These calculators use well-established formulas and typical construction practices for US residential projects. They are designed to give you a starting point — a number you can refine with your local supplier or contractor. Material quantities, waste factors, and footing spacing can vary by region, soil type, local code, and project specifics. Always verify before you buy.