People ask which decking is cheaper as if the answer were a single price per square foot posted somewhere official. It is not. A yard changes prices by the week, composite lines are not one product, and a 12×16 framed one way is a different pile of boards than the same rectangle framed the other way. This page uses the board calculator defaults and labels every dollar as an example you should overwrite.
The opening deck is 16 feet along the house by 12 feet out, boards along the house, 5 1/2 inch face, 1/8 inch gap, 10 percent waste. That buys 29 boards at 16 feet. Four hundred sixty-four linear feet are purchased. Twenty-six rows actually cover the deck. The extra three rows are the waste allowance, not a mystery fee.
Use the tag, not a rumor
The calculator’s starting decking price is $1.25 a linear foot. That is a rough big-box placeholder for pressure-treated 5/4×6 so the total is not zero. It is not a survey. If your yard wants $1.60, type $1.60. The board count does not change. The money does.
At the placeholder, 464 linear feet times $1.25 is $580 of decking. Joists on this layout are 13 boards, each spanning the 12 foot width. At the placeholder $1.60 a linear foot, joists are 13 × 12 × $1.60 = $249.60. One rim board along the 16 foot run is another $25.60. Screws, two per crossing and then 10 percent, are 744 screws. At $10 per 100 that is $74.40. The whole placeholder total is $929.60. You can read that breakdown on the calculator. Change any price and only that line moves.
The same boards in composite
Composite and PVC are often a different face width. Do not assume 5 1/2 inches. Measure the board or read the spec sheet, then type that width and the gap the manufacturer prints. A wider board means fewer rows. A required wider gap can give a row back. The count is the geometry, not the brand.
For a cost sketch only, imagine the geometry stays 464 linear feet and the composite tag says $3.50 a linear foot. That example is not an average and not a quote. It is 464 × $3.50 = $1,624 of decking, against $580 at the pressure-treated placeholder. The difference on this one line is $1,044 before tax. If your composite is $2.75 or $5.00, multiply 464 by that number instead of borrowing $3.50.
The joists and the rim do not become composite because the surface did. Most decks still frame with pressure-treated lumber under either surface. Leave the joist price alone unless your yard’s 2×8 is different. What changes is the fastener line, the waste you expect, and whether you will buy stain later.
Fasteners are a second price, not a rounding error
Face screws on the worked example are $74.40 at the placeholder. A hidden-clip deck often wants a clip at each joist crossing on the installed rows, plus starter clips along the first board and sometimes the last. Twenty-six rows times 13 joists is 338 crossings. If a clip in your hand costs $1.25, that example is about $422, and it replaces the screw dollars rather than sitting on top of them. Starter clips and butt-joint clips are extra. The fastener guide is the right place to see why you must not paste the screw total into a clip order.
Grooved composite boards are a matched system. The clip, the groove, and the gap are designed together. Mixing a bargain clip with a board it was not made for is how rows wander. Budget the system the manufacturer sells, not a generic “hidden fastener” line from a different brand.
What the first Saturday does not show
Pressure-treated wood moves as it dries. New boards are often too wet to stain. The stain calculator will still tell you gallons for later: the opening deck, two coats, 200 square feet per gallon, 10 percent waste, buys 3 gallons for the flat surface only. Rails and stairs are more. Composite cap stock is usually a wash-and-let-dry surface. Do not buy stain for it unless that manufacturer says the board accepts stain. Read the warranty that ships with the product you chose. This page will not invent a year count for how long either surface lasts.
Color is a purchasing problem, not a slogan. Wood stain can be refreshed and can also look blotchy if the first coat went on wet lumber. Composite color is set at the factory. Fading, if it is covered, is covered by that warranty’s words, not by a forum average. Buy enough boards from one lot, including waste, so a repair next year is not a different dye lot if you can help it.
A fair way to decide
Run the board calculator twice. First with the pressure-treated width, gap, and the price on today’s tag. Second with the composite width, the manufacturer’s gap, and that tag. Add clips or screws using the crossing count the page already did, at the price of the box you would actually pick up. Add joists once. They are shared. Add stain only on the wood path, and only for the year you will do it.
Then add the work you are willing to repeat. Wood often means a wash and a stain on a cycle you choose. Composite often means a wash and a closer reading of the installation sheet, including picture-frame borders and breaker boards the rectangle calculator does not draw. Neither path is “free after the boards.” The honest comparison is two receipts plus the maintenance you will really do.
If the composite list is several hundred dollars more on a 12×16 and you plan to stay in the house, that premium is buying the maintenance you skip and the look you want. If you might replace the surface in a few years, the pressure-treated list is the smaller check. The calculator will not make that call. It will keep the arithmetic from being the part you guess.