What DeckMath does
DeckMath is a free, contractor-grade calculator suite for residential deck design and budgeting. Every calculator is validated against IRC 2021 prescriptive tables — joist spans from R507.6, beam spans from R507.5, footing depths from R507.3, stair geometry from R311.7, and guard openings from R312.1.3. Pricing is 2026-Q1 retail data from Home Depot, Lowe's, RSMeans, Home Advisor, and Angi, with state-specific labor multipliers.
We currently ship 10 production calculators across structural design (joist span · beam span · footings), full project planning (deck material · deck cost · stair · baluster spacing), brand-deep estimators (composite-deck-cost · trex-deck), and maintenance (deck stain). Combined monthly search volume addressed: ~201,000.
What makes DeckMath different
- Real surface-area models — we count what other calculators skip (railing systems, baluster faces, stringer faces, board-edge waste). A typical "16×12 deck" is actually 600+ sq ft once stairs and railing are included.
- Cinematic 3D viewer for plan-level calculators (deck-material, deck-cost, composite-deck-cost, trex-deck) — Three.js + React Three Fiber, photoreal materials, HDR lighting, lazy-loaded so non-3D calculators stay under 200 kB First Load JS.
- Calc-appropriate SVG diagrams for structural calcs (joist span, beam span, footing cross-section, stair elevation, baluster layout, stain area breakdown) — pedagogically clearer than 3D for what they communicate.
- Real brand catalogs — 11 composite/PVC products with real per-LF retail (composite-deck-cost), 27 Trex colors with TUHF box counts (trex-deck), 13 stain brands with stocked-size bundles (deck-stain).
- Embed system — every calculator can be dropped onto any site with a one-line script tag. Free up to 1,000 calculations/hour per domain.
- No signups, no paywalls, no premium gates. Revenue comes from advertising and (eventually) affiliate links to retailers you'd shop at anyway.
Who builds DeckMath
DeckMath is built by SemiSoftwares, an independent software studio. The lead engineer is Muhammad Atif, a full-stack engineer with 10+ years of experience shipping production web applications. We also operate semisoftwares.com (an AI website builder), Pack Forge (Elementor token injection pipeline), and a handful of other developer-facing tools.
Our IRC compliance approach
IRC 2021 (the International Residential Code) is the model code most US jurisdictions adopt for one- and two-family residential construction. Section R507 is the prescriptive deck chapter — it covers everything from joist sizes to guard heights. DeckMath encodes the exact tables published in R507 (joist spans, beam spans, footing diameters by soil type) plus the related sections (R311 for stairs, R312 for guards, R403 for footings and frost depth).
When we say "IRC compliant" we mean the math matches the prescriptive tables verbatim. We do not claim to replace a licensed structural engineer for non-prescriptive designs (cantilever beyond 1/4 of joist span, cable-rail tension calcs, irregular load paths, decks attached to cantilevered house framing). For those cases, our calculators flag the input and recommend you stamp the design with a P.E.
Pricing accuracy
All prices reflect 2026-Q1 national-median retail data sourced from Home Depot Pro Desk, Lowe's Pro, RSMeans residential indices, Home Advisor, and Angi national surveys. We update quarterly. Local market variance can be ±15% — Northeast and West Coast markets typically run 1.22-1.28× the national labor average; suburban South runs 0.92×.
Privacy + data
DeckMath does not collect personal information. There are no user accounts. Calculator inputs live in your browser's localStorage and in the share-link URL parameters — nothing is sent to our servers. We use Google Analytics for aggregate page-view counts and (when applicable) Google AdSense for advertising. See the Privacy Policy for details.
Contact
Questions, bug reports, feature requests, or want a custom calculator built? Email [email protected] or reach out through the contact page. We read everything; we don't always reply but we always read.
Built with Next.js 14 + Three.js + Tailwind CSS. Deployed on a single VPS in Frankfurt. Open to acquisitions, partnerships, and homeowner war stories.