Data checked October 2026

Paint & Stain Calculators

Paint coverage depends on the product, the surface and how many coats you need. These calculators start from the coverage manufacturers actually publish, subtract doors and windows, and round to the cans you can buy so you are not left a quart short.

Paint CalculatorEnter your room size, doors and windows to get the exact gallons for walls, ceiling and trim, the cheapest mix of quarts, gallons and pails for your paint, primer, supplies and cost.Exterior Paint CalculatorEnter your house footprint, wall height and siding type to get gallons for siding and trim, the cheapest can mix, primer, supplies and cost — with stucco, brick and rough cedar adjusted.Deck Stain CalculatorEnter your deck or fence size to get gallons of stain for the floor, railings and stairs — by product, coats and wood condition — plus the cheapest can mix, supplies and cost.Wallpaper CalculatorA 12 × 12 ft room with 8 ft walls, one door and one window needs 28 strips of 20.5 in paper — 10 standard rolls (20.5 in × 33 ft) at three strips per roll. The repeat decides how many strips each roll gives, so the calculator counts strips, not square feet.

Quick answers

Common paint questions, already worked out

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