Estimate square footage, deck boards, and joists from your deck size, then add board pricing for a quick material cost — a fast takeoff before you write the quote.
Boards run this direction.
5.5 in is a standard 5/4x6.
1/8 in (0.125) is typical.
16 in OC is standard; 12 in for a stiffer deck.
Deck surface
144 sq ft
Counts round up so you never come up short. Board count assumes each board spans the full deck length — add pieces for butt joints on longer runs, plus ~10% for waste. Add rim joists, ledger, fasteners, labor, and margin for a full quote.
This is a fast material takeoff for the deck surface. It works from three simple formulas so you can sanity-check a job before you order lumber or send a quote:
The board count assumes each board spans the full deck length. On long runs you will have butt joints, so add extra boards and roughly 10% for waste. This tool covers the decking surface — a full estimate also needs the ledger, rim and beam framing, footings, fasteners, railing, labor, and your margin.
Material counts are only half the job. To win work and stay profitable, mark the materials up and layer in labor, overhead, and margin. The job pricing calculator does that cost-plus math for you. If decks are a service you are adding to a broader business, how to start a handyman business walks through licensing, pricing, and getting your first customers. Browse the rest of the free tools for more contractor calculators and generators.
Divide the deck width (in inches) by the board width plus the gap, then round up. A 12 ft wide deck with 5.5 in boards and a 1/8 in gap needs ceil(144 / 5.625) = 26 rows of boards, each spanning the deck length. Add roughly 10% for waste and any butt joints on longer runs.
16 inches on center is the standard for residential decks with most composite and 5/4 wood decking. Drop to 12 inches on center for a stiffer feel, for diagonal board layouts, or when the decking manufacturer requires it. Always follow the decking and local code requirements.
Multiply the deck length by the width in feet. A 12 ft by 12 ft deck is 144 square feet. For L-shaped or multi-level decks, split the deck into rectangles, calculate each one, and add the results together for the total surface area.
Yes. The deck calculator is completely free with no signup and no credit card, and it runs entirely in your browser. When you are ready to quote the job and schedule the crew, Fieldtics has a free tier for that too.
Size it here, then run the whole job in Fieldtics — quotes, scheduling, and invoicing in one free app. The free tier covers unlimited clients, job scheduling, a customer CRM, and the mobile app with no credit card. The $29/mo Professional tier adds quotes, invoicing, online payments, and team scheduling. Trusted by 500+ service businesses.