Estimate deck staining or sealing cost by deck area.
Staining a deck costs far more than the floor area suggests, because railings dominate the work. Every linear foot of railing carries roughly four square feet of paintable surface once you count balusters on both faces, the top cap and the rails, and each of those surfaces is brushwork rather than a roller pass — so railing takes about twice as long per square foot as open decking. Coverage is the other figure to respect: manufacturers quote 250 to 400 square feet per gallon, but bare or weathered timber drinks the first coat and can halve that, which is why the second coat always goes further than the first. Buying in whole gallons and allowing for the odd spill means the practical order is a little above the calculation.
Stain quantity and cost including railings
Railing area = railing feet x 4; paintable area = deck area + railing area; gallons = ceiling(paintable area x coats / coverage); labour = (deck area + railing area x 2) x labour rate
Because it is nearly all detail. Balusters have two faces plus edges, the cap and rails need cutting in, and none of it can be rolled — forty feet of railing can take longer than the entire deck floor.
On bare or previously stripped timber, yes. The first coat is largely absorbed and gives little protection; the second builds the film that actually resists water and UV. A maintenance recoat on sound stain can be a single coat.
Cleaning, stripping and sanding, which on a weathered deck can equal the staining cost, plus replacing any rotten boards. Preparation is where a stain job succeeds or fails.