Deck Board Calculator
Estimate 16 ft deck board quantities from deck dimensions, board width and direction.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Estimate the number of 16 ft deck boards from the deck dimensions, board width, laying direction and waste allowance. The estimate assumes a 1/4 in gap and does not size joists, beams, posts or footings.
Worked example
calculated with the default values below
Deck length 16 ft · Deck width 12 ft · Deck board width 5.5 in · Board direction Boards run across the width · Waste allowance 10 % Deck area 192.0 sq ft · Deck boards (16 ft lengths) 38
General background references
Disclaimer
These calculators provide planning estimates only. Building codes, wiring regulations and safety requirements differ by country and change over time, and nothing here replaces a licensed professional or a permit. For structural, electrical or gas work, follow local code and have the installation inspected.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
A = LW; B = ⌈⌈12s ÷ (w + 0.25)⌉ × ⌈r ÷ 16⌉ × (1 + q ÷ 100)⌉
- A
- Area (sq ft)
- L
- Length (ft)
- W
- Width (ft)
- s
- Span (ft)
- r
- Run (ft)
- w
- Board width (in)
- q
- Waste percent
- B
- Boards needed
Board count = ceil(ceil(span × 12 / (board width + 0.25 in)) × ceil(run / 16 ft) × (1 + waste/100)). Assumes 16 ft boards, a 1/4 in gap and no offcut reuse; this estimate does not size the supporting structure.
Frequently asked questions
How does board direction affect the estimate?
The estimate counts rows using the selected direction, a 1/4 in gap and nominal 16 ft boards, then applies the waste allowance. It does not account for cut planning or reuse of offcuts, and it does not calculate joists, beams, posts or footings.