Wall & Ceiling Calculators
Paint, drywall and wallpaper - by the room, not just the wall. 5 free calculators.
A wall and ceiling estimate goes wrong for the same reason almost every time: it treats a room as one flat rectangle instead of several walls, a ceiling, and a set of doors and windows that don't need coverage.
These calculators handle multiple walls with their own openings in one estimate, then round up to what you can actually buy - whole gallons, full sheets of drywall, or a wallpaper roll count that accounts for pattern repeat.
Last reviewed September 2026
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All 5 Wall & Ceiling calculators
Paint Calculator
Use this paint calculator to find the gallons of paint and primer a room needs, with doors, windows, the ceiling, and coats factored in. Wall area shown too.
Drywall Calculator
Drywall calculator for sheets, screws, and joint compound, with doors, windows, the ceiling, and waste factored in. Pick 4x8 or 4x12 sheets and 1/2 or 5/8 in.
Wallpaper Calculator
Wallpaper calculator for the double rolls a room needs. Roll width, pattern repeat, and waste are all included, with standard 20.5 in. or wide 27 in. rolls.
Insulation Calculator
Insulation calculator for batt, blown-in, or rigid foam. Get the packages a wall, ceiling, or attic needs from your product's rating, with waste added.
Spray Paint Coverage Calculator
Spray paint coverage calculator for furniture, trim, and crafts. Enter the area, the number of coats, and your can's rated coverage to get the cans to buy.