Estimate deck board count from deck width, board width and gap.
Calculator
Result Summary
Review the main answer, supporting values, chart breakdown, and calculation details.
Result Breakdown
Calculation Details
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How it works
Estimate deck board count from deck width, board width and gap. Use the units shown in the calculator and review every assumption before using the result.
Formula
Board count ≈ ceil(deck width ÷ (board width + gap)).
Worked example
A 20 ft deck using 5.5 in boards with 1/8 in gaps requires roughly 43 boards across the width.
Important assumptions
This tool is designed for planning and comparison. Real-world prices, manufacturer ratings, building requirements, lender terms, electrical codes, tolerances, and product specifications can vary.
Frequently asked questions
Is this calculator free?
Yes. It runs in your browser and does not require an account.
Are the results exact?
The math is deterministic for the entered values, but the result depends on inputs and assumptions. Verify safety-critical, financial, code-related, towing, fitment, and manufacturer-specific decisions with authoritative information.