Who it is for
You have a rectangular deck in mind, or a deck that is already standing, and you want a count you can take to the store. Boards by length. Gallons of stain. Bags of mix for a round tube. Balusters for a rail. The site is built for that errand.
It is not built to replace a framer, an engineer, or the person at the permit counter. Span tables, ledger bolts, frost depth, guard height, and stair geometry are local rules plus the load on your particular deck. Those decisions stay with you and with whoever signs the plan.
Why it exists
A lot of deck calculators jump straight to code spans and beam sizes. That is useful later, and it is easy to get wrong on a web page that has never seen your house. The first expensive mistake for a homeowner is usually simpler: buying the wrong number of boards because square footage was treated as a board count, or because the boards were assumed to run the other way.
DeckBoardCalc stays on that shopping problem. The board calculator counts rows, picks stock lengths you say the yard sells, adds a waste percent you can change, and prices the list with numbers you type. The defaults are a ballpark for pressure-treated decking so the page is not blank. They are not a quote.
How the estimates work
Deck boards stack across the deck with a gap between them and no gap after the last board. The row count is (across + gap) ÷ (board width + gap), rounded up. Each row is then covered by an 8, 10, 12, or 16 foot board, whichever checked length wastes less linear footage after your waste percent. If one board can be cut into two full rows, it counts twice. If nothing reaches, the row is spliced and the cut plan says so. Offcuts are not pretended to start another row.
Joists, when you leave them on, are one at each end of the run plus one at every spacing you pick. The last bay is shorter when the length does not divide evenly. Screws are two per board per joist, then the same waste percent. Hidden clips are a different product. The screw line is not a clip count. The fastener guide explains that split.
Stain is area times coats, divided by the square feet per gallon on the can, then rounded up to whole gallons. Footing bags are the volume of a cylinder divided by the yield printed on the bag. Balusters are the smallest number that keeps every opening, including the ends, at or under the gap you type. Each tool has a worked example on its own page. The board math is also written out under the list on the home page.
What stays on your computer
The calculators run in the browser. Nothing you type is uploaded to DeckBoardCalc, because there is no DeckBoardCalc account and no DeckBoardCalc server behind the forms. The pages are static files. See the privacy policy for the hosting and advertising pieces, which are separate from the math.
What to read next
- All four calculators
- Guides, including common deck sizes and a lumberyard order
- Terms and disclaimer
- Contact