Deck staining is priced by the square foot, but the square footage is the least interesting part of the quote. The example rates above, $2.50 per square foot for one coat and $3.75 for two, only make sense once you see where the hours actually go.
The stain is the last hour of the job
Most of a staining job happens before the can opens: washing the deck, waiting for it to dry, sanding handrails and worn traffic paths, masking siding and plants. That prep happens once whether you apply one coat or two, which is exactly why the example two-coat rate is $3.75 and not double the $2.50 single-coat rate. The second coat is just application. The first coat carries the prep.
On a 12 by 16 deck, 192 square feet, the example math is $480 for one coat and $720 for two. If a customer balks that stain costs a fraction of that at the store, walk them through the prep list. It is the difference between a finish that lasts and a coat of color on dirty wood.
Rails and spindles eat the clock
Floor boards spray or roll fast. Spindles are brushwork, four faces each, at hand height, forever. Two decks with identical floor area can be very different jobs if one sits at grade with no rails and the other carries railing on three sides.
Decide how your rate handles that: either bake typical railing into the per-square-foot number and adjust when a deck has none, or carry railing as its own line. What loses money is quoting a spindle farm at a floor-only rate because the square footage looked small.
Recoat work is repeat work
Wood decks recoat on a cycle for as long as they exist, so every staining customer is a future customer. Text the quote fast, do the prep right, and you become the number they call every time the water stops beading. A clean itemized text does half of that, and the quote template for texting customers shows the format.
Some of those customers will eventually ask about never staining again. That is the wood vs composite deck conversation, and it is worth knowing cold.
The rates here are examples. PriceDesk runs this calculator with your own per-coat rates and add-ons, on your phone, quote in about ten seconds. Free for 14 days, no card required.