Washington Deck Calculator
Deck boards, fasteners, and total cost for your deck size. Cost estimates adjusted for Washington — about 5% above the national average.
Last reviewed July 2026 · Free · Nothing you enter is stored
Washington pricing
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Estimates use 2026 national averages adjusted by Washington's construction cost index (1.05). Always get local quotes.
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Deck costs in Washington
Washington's overall construction pricing runs about 5% above the national average, based on published location cost factors that blend local labor rates and material prices. This page applies that 1.05 index to the national averages in our deck calculator, so the material quantities are identical — it's the dollar estimates that shift to Washington levels.
How this calculator works
Board math uses standard 5.5"-wide decking with a 1/4" gap: 2.09 linear feet of board per square foot of deck, plus 10% waste (15% for diagonal layouts). Hidden fasteners or screws run about 3.5 per square foot. Cost estimates use 2026 installed averages — $35/sq ft pressure-treated, $57/sq ft composite — and a DIY materials-only average around $20/sq ft.
Frequently asked questions
How much does deck cost in Washington?
Construction pricing in Washington runs about 5% above the national average (cost index 1.05 vs. 1.00 national). This calculator applies that factor to 2026 national average prices to produce Washington-adjusted estimates. Local quotes can still vary by metro area, season, and contractor demand.
Is it cheaper to DIY or hire a pro in Washington?
Labor is the bigger share of installed cost, so in Washington, the DIY-vs-pro math tracks the national picture. The calculator shows both estimates so you can compare.
Are these Washington prices exact?
No — they're planning estimates: national survey averages adjusted by a published state cost index. Prices differ between cities within Washington, by material grade, and by season. Use these numbers to budget and sanity-check quotes, not to replace them.
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