Free OnlineCalculators & Converters
Deck Calculator
Calculate deck boards, screws, and joists needed for a wood or composite deck.
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Key Features — Deck Calculator
Board count with waste
Screw estimate
Joist count at 16" OC
Configurable board width and gap spacing
Why Use This Tool — Deck Calculator
Free Online Deck calculatorDeck boards calculator — for EveryoneFast & Easy How many deck boards do i needDeck material calculator — 100% Free
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Works Everywhere
Use on any device — desktop, tablet, or phone. No downloads or plugins needed.
Frequently Asked Questions — Deck Calculator
How many deck boards do I need?
Divide deck width by effective board width (board + gap), multiply by board lengths needed, add 10–15% waste.
What gap between deck boards?
Standard is 1/4" gap. Composite decking often specifies 3/16–1/4". Gaps allow drainage and expansion.
How many screws for decking?
Use 2–3 screws per board per joist crossing — about 320 screws per 100 sq ft.