How many deck boards do I need for a 12x16 deck?

A 12x16-foot deck using standard 5/4x6 (5.5-inch wide) boards needs approximately 35 boards at 16-foot lengths, or 53 boards at 12-foot lengths (with butt joints). With 10% waste, order 39 or 58 boards respectively. Using 16-foot boards eliminates butt joints on the 16-foot dimension, creating a cleaner look.

What size deck boards should I use?

The most common deck board is 5/4x6 (actual 1 inch x 5.5 inches). This provides a good balance of strength, appearance, and cost. For heavy commercial traffic, 2x6 boards (1.5 x 5.5 inches actual) offer more stiffness. Composite boards come in 5.5-inch and 7.25-inch widths. Wider boards cover area faster but are more prone to cupping.

How far apart should deck boards be spaced?

Leave 1/8 to 1/4 inch between deck boards for drainage and airflow. For pressure-treated boards installed wet (fresh from the lumberyard), butt them tightly together - they will shrink to the proper gap as they dry over 2 to 4 weeks. Composite boards should always be gapped per the manufacturer's instructions, typically 3/16 to 1/4 inch.

How long do deck boards last?

Pressure-treated pine deck boards last 10 to 15 years with annual sealing. Cedar lasts 15 to 20 years with periodic maintenance. Composite decking lasts 25 to 50 years with minimal maintenance. Untreated wood decking can fail in as little as 3 to 5 years in wet climates. The substructure (joists and beams) typically outlasts the deck boards if properly built with treated lumber.

Should I use screws or nails for deck boards?

Deck screws are strongly preferred over nails. Use #8 or #10 coated deck screws, 2.5 to 3 inches long, with two screws per board at each joist. Screws hold better over time, resist popping, and allow easy board replacement. Hidden fastener systems (like Camo or Tiger Claw) create a screw-free surface appearance.

How much does deck board material cost?

Pressure-treated 5/4x6 deck boards cost $1.50 to $3.00 per linear foot ($18 to $36 per 12-foot board). Cedar runs $3.00 to $5.00 per linear foot. Composite ranges from $4.00 to $12.00 per linear foot. For a 12x16-foot deck, material cost for the deck boards alone ranges from about $600 (treated pine) to $2,400 (premium composite).

Deck Board Calculator

How many deck boards do I need? Free calculator for treated, cedar & composite boards — gives board count, linear metres, and waste factor.

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Need a more specific calculation? Try one of these:

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Deck stair calculator: How many steps and stringers? Free tool — enter deck height for step count, stringer quantity, and tread boards.

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How to Use This Calculator

1Measure the total length and width of your deck in feet.
2Enter the board width in inches - standard deck boards are 5.5 inches (nominal 2x6) or 3.5 inches (nominal 2x4).
3Enter the board length - common lengths are 8, 10, 12, 16, and 20 feet.
4Click Calculate to get the total number of boards, linear footage, and area coverage.

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About This Material

Deck boards are the visible surface of your deck and take the most wear from foot traffic, furniture, weather, and UV exposure. The most common material choices are pressure-treated lumber, cedar, redwood, and composite decking. Pressure-treated southern yellow pine (SYP) is the most popular choice for budget-conscious projects. Standard 5/4x6 (1 inch thick by 5.5 inches wide) deck boards cost $1.50 to $3.00 per linear foot and are rated for ground contact when treated to 0.40 pcf retention. Boards are available in 8, 10, 12, 16, and 20-foot lengths. The treatment protects against rot and termites but requires annual sealing or staining to prevent graying, warping, and splitting. Expect a 10 to 15-year lifespan with proper maintenance. Cedar and redwood are naturally rot-resistant softwoods prized for their appearance. Western red cedar deck boards run $3.00 to $5.00 per linear foot, while redwood ranges from $5.00 to $8.00. Both species are softer than treated pine and dent more easily, but they are dimensionally stable and less prone to warping. Cedar decks last 15 to 20 years with periodic sealing. Composite decking (Trex, TimberTech, Fiberon) is made from wood fibers and recycled plastic. Prices range from $4.00 to $12.00 per linear foot depending on the product line. Composites never need staining, resist rot and insects, and carry 25 to 50-year warranties. However, they require specific fastening systems, expand and contract with temperature, and can get very hot in direct sunlight. Most composite boards are 12, 16, or 20 feet long. Board spacing is critical: maintain a 1/8 to 1/4-inch gap between boards for drainage and ventilation. For pressure-treated boards installed wet, butt the boards tight - they will shrink as they dry. For kiln-dried and composite boards, leave the full gap during installation.

Next Steps:

Deck Footing Calculator →Deck Railing Calculator →Deck Stair Calculator →

Installation Tips

•Start the first board perfectly straight and square to the house - every subsequent board follows this line.
•Pre-drill the ends of boards within 2 inches of the edge to prevent splitting, especially with treated lumber.
•Stagger butt joints by at least 2 board positions for a stronger, more attractive deck surface.
•Crown boards upward (the bark side down) so water runs off rather than pooling on the surface.
•Leave a 1/4-inch gap between the house wall and the first deck board for drainage and expansion.

Common Mistakes to Avoid

Not leaving gaps between boards - tight-butted dry boards will buckle when they absorb moisture and expand.
Using too-short screws - deck screws should penetrate at least 1.5 inches into the joist for proper holding power.
Ignoring grain direction - installing boards bark-side up causes cupping and water pooling on the surface.
Running all butt joints over the same joist - this creates a visible line and weakens the deck structure; always stagger joints.
Skipping end sealer on cut ends - untreated cut ends absorb water and rot faster than the treated faces of the board.