Free Construction & Renovation Calculators
No sign-up, no email, nothing to install. Enter your measurements, get the numbers you need, and check them against the building code before you spend money on materials.
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Stair Stringer CalculatorRiser height, tread depth, stringer length, cut angle and throat depth — with an IRC code check.
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Deck Board CalculatorHow many deck boards to buy, linear feet, joists and screws — with a check against the IRC decking spans.
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Deck Post & Footing CalculatorHow many posts, how far apart, the beam size and the concrete for each footing — with the IRC spans and the frost-depth rule.
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Fence Picket CalculatorEven picket spacing across any run, with the post layout, the rails and the concrete for each hole.
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Stud Spacing CalculatorStuds, plates and cut lengths for a wall at 12, 16 or 24 in on centre — with the openings, the corners and the IRC check.
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Crown Molding CalculatorMiter and bevel angles for 38° and 45° crown at any corner angle, plus the linear feet and pieces to buy.
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Wainscoting CalculatorEqual panel widths for board and batten or picture frame wainscoting, with the stile count and the material to buy.
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Tile Layout CalculatorTiles across and down, the size of each edge cut, and the boxes to buy — with the grout joint counted as the module it is.
Why these are free
Because they cost almost nothing to run. Every calculator on this site runs entirely in your browser — nothing is sent to a server, nothing is stored, and there is no account to create. The site is supported by advertising.
About the numbers
Where the International Residential Code governs the work, each calculator checks your layout against the relevant section, so you can see at a glance whether it is legal before you cut anything. Where the code does not govern it — crown molding, wainscoting and tile are finishes, and the IRC says nothing about any of them — the page says so plainly instead of inventing a section number. Codes vary by state and county, so always confirm with your local building department before starting work.