7 free tools · one engine
Deck calculators
Each tool reads the real IRC R507 deck span tables. Start with whichever part of the deck you're sizing — they all run on the same code-compliant engine.
Free deck joist span calculator: find the maximum span for 2x6, 2x8, 2x10 and 2x12 joists at 12, 16 or 24 inch spacing, straight from the IRC R507.6 deck table.
OpenFree deck beam span calculator: how far a 2-ply or 3-ply 2x8/2x10/2x12 deck beam can span between posts, from the IRC R507.5 table, based on the joist span it carries.
OpenFree deck footing calculator: get the footing diameter from your post load and soil bearing, the depth below your state's frost line, and the concrete (bags) each pier needs (IRC R507.3).
OpenFree deck stair calculator: enter your deck height to get the number of risers, the exact riser height, tread run and total stair run to IRC R311.7 code.
OpenFree deck cost calculator: estimate the cost to build your deck by size and material, from a DIY lumber budget up to a contractor-installed price.
OpenFree deck material calculator: how many deck boards, screws and lineal feet of framing your deck needs, plus a material cost estimate by decking type.
OpenFree deck railing & baluster spacing calculator: get the exact number of balusters and an even gap that passes the IRC 4-inch sphere rule for your railing length.
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