Deck Board Calculator
Work out how many deck boards and the linear feet you need from the deck size, the board width and the gap, with a waste allowance for cuts.
Read the guide: How Many Deck Boards Do I Need?Deck boards
Boards needed
29
26 rows · 457.6 ft of decking
- Rows of boards
- 26
- Deck area
- 192 ft²
- Linear feet (no waste)
- 416 ft
- Linear feet (+10% waste)
- 457.6 ft
Boards run the full 16 ft width, stacked across the 12 ft depth with a 0.25 in gap for drainage.
Counts the deck surface only. Add framing, fascia, stairs and any picture-frame border separately, and round up to whole boards at the yard.
How it works
- 1
Enter the deck size
Add the width the boards run across and the depth they stack up over.
- 2
Set the board
Enter the board face width, the drainage gap and the length of stock you buy.
- 3
Get the count
See the rows, the linear feet and the number of boards, waste included.
Instant & 100% private — nothing is uploaded
Every calculation runs locally in your browser. The income, balances and goals you enter stay on your own device and are never sent to a server — nothing is stored, logged or shared.
Frequently asked questions
- How many deck boards do I need?
- Divide the deck depth by one board width plus the gap to get the rows, then multiply by the deck width for the linear feet. The calculator does this and converts it into whole boards of your stock length.
- What gap should I leave between deck boards?
- About an eighth to a quarter inch lets water drain and the boards breathe. Grooved composite boards often set their own gap with hidden clips.
- Why add a waste percentage?
- Cuts, the odd warped board and a picture-frame border all eat material. Ten percent is a safe starting point for a simple rectangular deck.
- Are these numbers exact?
- They are close planning estimates, not a substitute for a contractor takeoff. Real quantities depend on your terrain, post spacing, waste and local building code, so buy a little extra and confirm against your supplier.
- Is my fence design sent anywhere?
- No. Everything runs in your browser. The layout, lengths and prices you enter stay on your device, nothing is uploaded, logged or stored, and it all clears when you close the tab.
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