Decking Boards, Joists & Screwsdiy

Outdoor Decking Board, Subframe Joist & Fastener Screw Calculator

Calculate total linear feet or meters of timber/composite deck boards, subfloor joists (16" / 40cm on-center spacing), and deck screws needed with a 10% waste buffer.

Calculator Inputs

Live Real-Time
m
Quick select:
m
Quick select:
mm
Quick select:
Calculated ResultDecking Boards, Joists & Screws

Total Deck Board Runs Needed (10% Waste Included)

28boards

Subframe Support Joists Count (40cm Spacing)

14 joists

Total Decking Fastener Screws

784 screws

Detailed Calculation Breakdown

Deck Total Area
17.5 m²
Structural Joists
14 joists
Deck Boards
28 boards

Calculation Methodology

Total Deck Boards = ceil(Deck Width / (Board Width + Gap)) * 1.10. Number of Joists = floor(Deck Length / 0.40m) + 1. Screws Count = Joists * Boards * 2.

Important Legal & Educational Disclaimer

Always maintain 3mm–6mm (1/8" to 1/4") gaps between decking boards for proper thermal expansion and rainwater runoff drainage.

This calculator is designed for educational and informational purposes only based on public statutory frameworks. The outputs do not constitute binding financial, tax, or legal advice. We assume no liability for decisions made based on these estimations. Always verify with the relevant official authorities or a certified professional advisor.

Frequently Asked Questions

Standard structural carpentry requires 2 deck fasteners per board at every supporting joist crossing to prevent board cupping and warping.
Related Calculators

Related Calculators

Recommended tools and calculators tailored to your current calculation

Explore all tools