Deck planning guide

How Many Deck Boards Do I Need?

This quick-reference chart assumes 5.5-inch actual-width decking, a 1/8-inch gap, boards running along the first listed dimension, and 10% extra decking for cuts and waste.

Decking needed by deck size

Deck sizeAreaDecking to buy
8 × 10 ft80 ft²194 linear ft
10 × 10 ft100 ft²243 linear ft
10 × 12 ft120 ft²286 linear ft
12 × 12 ft144 ft²344 linear ft
12 × 16 ft192 ft²463 linear ft
14 × 16 ft224 ft²539 linear ft
16 × 16 ft256 ft²616 linear ft
16 × 20 ft320 ft²757 linear ft
20 × 20 ft400 ft²947 linear ft
20 × 24 ft480 ft²1,144 linear ft

Linear-foot quantities depend on board direction, actual board width, gap and waste. They are not a structural framing design.

How deck board quantity is calculated

First determine how many board rows fit across the deck width using the actual board width plus the installed gap. Multiply the number of rows by the board run length, then add an allowance for cuts and waste.

Example: 12 × 16 deck

With boards running 12 feet and rows spanning the 16-foot dimension, 5.5-inch decking with a 1/8-inch gap requires about 463 linear feet including 10% extra.

Calculate the complete deck

Use your actual board width, gap, joist spacing, footing dimensions and waste allowance.

Open Deck Materials Calculator →

For joists, screws and footings, browse the Deck Planning Hub.