Deck Board Calculator
Boards, screws, joists and cost for a deck of any size.
Enter your values
ⓘ Live results
Results
- Deck boards
- 26 (+10%: 29)
- Board rows
- 26
- Joists at 16 in o.c.
- 13 x 12 ft
- Screws (2 per joist crossing)
- 676
- Decking cost
- $638.00
- Deck area
- 192 sq ft
Working
- 126 rows x 1 board(s) per row = 26 boards
Quick answer
Board rows = deck width divided by board width plus gap; multiply by deck length and divide by board length to get pieces.
rows = deck width / (board width + gap)
How to use the Deck Board Calculator
- 1Enter the deck footprint, then the actual board width (5.5 in for a nominal 6 in board).
- 2Set the expansion gap - 1/4 in for wood, check the maker's spec for composite.
- 3Add 10% for cuts, mitres and picture-frame borders.
Worked example
Using the values the calculator loads with:
Inputs
- Deck length16 ft
- Deck width12 ft
- Board width5.5 in
- Gap between boards0.25 in
- Board length sold16 ft
- Cost per board22 $
Results
- Deck boards26 (+10%: 29)
- Board rows26
- Joists at 16 in o.c.13 x 12 ft
- Screws (2 per joist crossing)676
- Decking cost$638.00
- Deck area192 sq ft
- 26 rows x 1 board(s) per row = 26 boards
Frequently asked questions
What gap should I leave between deck boards?
About 1/4 inch for dry hardwood or composite. Pressure-treated lumber that is still wet can be laid tight because it shrinks as it dries.
How many screws will I need?
Two per board per joist crossing. This tool counts them for you, and it is worth buying 10% extra.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.