Deck Board Calculator
Enter your deck size and board dimensions to get how many deck boards and total linear feet to buy, with waste built in.
Deck & boards
You'll need
Deck area0 sq ft
Deck boards (16 ft)
0
0 total linear feet
Boards run perpendicular to the joists. Add joists, beams, and fasteners separately (~350 screws per 100 sq ft).
How to estimate decking
Each board covers its (width + gap) × length in area. Divide the deck area (plus waste) by that coverage for the board count. Joists, beams, posts, and fasteners are estimated separately.
Take off the whole deck build in minutes
ProBuildCalc turns your iPhone's LiDAR scanner into a job-site measuring kit — walk the space and it captures the square footage, material takeoff, and a blueprint automatically. No tape measure, no graph paper.
Deck calculator FAQ
- How many deck boards do I need?
- Divide your deck's square footage (plus ~10% waste) by the coverage of one board — its width plus the gap, times its length. A 5.5-inch board with a 1/8-inch gap covers about 0.47 ft per foot of length.
- How much gap should I leave between deck boards?
- Leave about 1/8 inch for pressure-treated lumber that's still wet (it shrinks as it dries) and 1/8–1/4 inch for dry or composite boards for drainage.
- How much waste should I add for decking?
- Add about 10% for straight, parallel boards and 15% for diagonal or picture-frame layouts that need more cuts.
- How many screws for a deck?
- Plan on roughly 350 deck screws per 100 square feet — two per board at each joist crossing.