Paint & Walls Calculators

Paint, primer, drywall and wallpaper estimates.

Wall work is estimated from one number, the wall area: perimeter times height minus doors and windows. From that area the calculators here give gallons of paint or primer, sheets of drywall with screws and compound, rolls of wallpaper by pattern repeat, and bags of stucco or plaster.

Coverage figures are the manufacturer's typical values, 350 to 400 square feet per gallon of paint, 32 square feet per 4 x 8 sheet of drywall, 1.25 gallons of joint compound per 100 square feet. Textured walls, bare drywall and dark color changes use more, and each tool has a field for it.

How much material do I need

Quantities to order, in the units a supplier sells them in. 14 calculators.

Paint CalculatorWork out how many gallons of paint you need for a room. Enter the room size, doors, windows and number of coats to get wall, ceiling and total paint quantities.Drywall CalculatorCalculate how many sheets of drywall you need for a room, plus screws, joint compound and tape. Supports 4x8, 4x10 and 4x12 sheets with or without the ceiling.Paint Primer CalculatorCalculate how many gallons of paint primer you need for a room from the wall area, doors, windows and the surface: painted walls, new drywall, bare wood or a dark color.Ceiling Paint CalculatorCalculate how many gallons of ceiling paint you need from the room size, number of coats and ceiling texture. Popcorn and textured ceilings soak up more paint.Wallpaper CalculatorCalculate how many rolls of wallpaper you need for a room from the wall height, perimeter, roll size and pattern repeat, with strips per roll and strips needed.Crown Molding CalculatorCalculate how many linear feet of crown molding a room needs and how many 8, 12 or 16 ft pieces to buy, with inside and outside corner counts, finish nails and cost.Joint Compound CalculatorCalculate how many gallons and buckets of joint compound you need to tape, finish or skim coat drywall, plus rolls of paper or mesh tape and the weight to haul home.Wall Square Footage CalculatorCalculate the square footage of the walls in a room from its length, width and ceiling height, minus doors and windows, for paint, drywall, wallpaper or tile.Stucco CalculatorEstimate bags of base coat and finish coat stucco, metal lath sheets and building paper for a wall, for a traditional three-coat or a one-coat stucco system.Plaster CalculatorEstimate bags of veneer plaster or gypsum basecoat, blueboard or lath, and mixing water for a wall, with coverage for skim coat, basecoat and two-coat plaster.Wainscoting CalculatorUse this wainscoting calculator to lay out board and batten, beadboard, raised panel or picture frame wainscot in equal bays and count battens, cap rail and base.Drop Ceiling CalculatorA drop ceiling calculator that counts main tees, cross tees, wall angle, hanger wire and tiles for a suspended grid, with matching border cuts on opposite walls.Shiplap CalculatorThis shiplap calculator turns wall length and height into boards, linear feet and rows using the real face coverage of each profile, with the final ripped row called out.Exterior Paint CalculatorExterior paint calculator for a whole house. Enter the footprint, stories, gables and siding type to get gallons of body paint, trim paint and primer to buy.

What will it cost

Line item budgets built from current US material and labor rates. 3 calculators.

Paint Cost CalculatorEstimate what it costs to paint a room: gallons of paint and primer to buy, material cost, optional pro labor per square foot and the cost per square foot of wall.Popcorn Ceiling Removal Cost CalculatorA popcorn ceiling removal cost calculator that prices scraping, skimming or covering by area, build year, painted texture and ceiling height, with asbestos testing.House Painting Cost CalculatorHouse painting cost calculator for a whole home inside, outside or both. Prices labor and paint by floor area, stories, siding type and how much prep it needs.

A typical project, in order

Carry each result into the next tool.

1Wall Square Footage CalculatorWall area minus openings, used by every tool below
2Drywall CalculatorSheets, screws, compound and tape
3Joint Compound CalculatorBuckets for taping or a skim coat
4Paint Primer CalculatorSeal new drywall or a color change
5Paint CalculatorGallons for the walls
6Ceiling Paint CalculatorFlat paint for the ceiling
7Paint Cost CalculatorMaterials and labor budget

Paint & Walls questions

How much paint do I need per square foot of wall?

About 1 gallon per 350 to 400 square feet per coat. A 12 x 12 room with 8 ft ceilings has roughly 334 square feet of wall after openings, so 2 gallons for two coats.

Do I subtract doors and windows from wall area?

Yes. Deduct about 20 square feet per door and 15 per window. On a wall with a large picture window or patio door, deduct its actual size.

How many sheets of drywall for a room?

Total surface area (walls plus ceiling) divided by 32 for 4 x 8 sheets, plus 10% waste. A 12 x 12 room with an 8 ft ceiling takes about 17 sheets.