Decking Calculator -

What is a Decking Calculator?

A Decking Calculator is a tool designed to help homeowners and contractors plan their deck projects efficiently. By inputting the dimensions of the deck and the materials being used, it accurately estimates the quantity of decking boards required to cover the surface.

This calculator also accounts for the small gap left between boards for drainage and expansion, and it includes a standard waste factor (10%) to account for cuts, mistakes, or unusable board sections. The fastener estimate assumes joists are spaced 16 inches on center.

Decking Material Comparison

Material	Average Cost/Sq. Ft.	Lifespan	Maintenance
Pressure-Treated Wood	$4 - $8	15-20 years	High (stain/seal every 1-2 years)
Composite	$9 - $16	25-30 years	Low (occasional cleaning)
Cedar / Redwood	$6 - $12	20-25 years	Medium (annual sealing recommended)
PVC	$10 - $15	30+ years	Very Low (cleaning only)

How to Use the Decking Calculator

Deck Dimensions: Enter the total length and width of the deck area you want to cover.
Board Width: Select the actual width of a single decking board (e.g., a "5/4 x 6" board is actually 5.5 inches wide).
Gap Size: Input the desired gap spacing between each board (e.g., 1/8 inch or 0.125).
Board Purchase Length: Enter the length of the individual boards you plan to buy (e.g., 8, 12, or 16 feet).
Calculate: Get an estimate for the total boards, total area, and the number of screws needed.

Number of Boards vs. Deck Width

Based on a 20ft deck length, using 16ft long, 5.5" wide boards

Frequently Asked Questions (FAQ)

Is a waste factor included in the calculation?

Yes, this calculator automatically adds a 10% waste factor to the total number of boards. This is a standard industry practice to account for material lost during cutting and to allow for unusable pieces.

Does this calculator estimate materials for stairs or railings?

No, this calculator is designed to estimate materials for the main flat surface (decking) only. It does not calculate requirements for the substructure (joists, beams), stairs, or railings.