Home & Construction

Decking Material Calculator

Estimate deck area, decking linear feet and board count from deck dimensions, board size, spacing and waste.

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How to use this decking material calculator

Enter the requested values above and select Calculate. Change any input to compare scenarios.

Formula and method

Board runs ≈ deck width ÷ (board width + gap). Total linear feet = board runs × deck length. Board count = linear feet ÷ board length, adjusted for waste.

Example

For a 12 × 16 ft deck using 5.5-inch boards with a 0.25-inch gap and 16-ft boards, the calculator estimates the number of board runs and boards before waste.

Important assumptions

Actual layouts can require starter boards, picture framing, breaker boards, trimming and manufacturer-specific spacing. Use the result as a planning estimate.

Frequently asked questions

What does the Decking Material Calculator calculate?

Estimate deck area, decking linear feet and board count from deck dimensions, board size, spacing and waste.

How does the calculation work?

Board runs ≈ deck width ÷ (board width + gap). Total linear feet = board runs × deck length. Board count = linear feet ÷ board length, adjusted for waste.

Is this calculator free?

Yes. ERICH Calculators is free to use and no account is required.

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Method, assumptions & corrections

See how formulas, sources and limitations are handled across ERICH Calculators.