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Wallpaper, Paint and Flooring Calculator

Measure the room once and get wallpaper rolls, paint and flooring in one go. Switch to meters if you prefer.

Estimate materials

Units

Most US ceilings are 8 to 9 ft.

Each counts as 20 sq ft (a 36 × 80 in door). Blank = 1.

Each counts as 15 sq ft (3 × 5 ft). Blank = 1.

Coats of paint

Blank = 56 sq ft, a US double roll (20.5 in × 33 ft). Check your label.

Blank = 10%. Use more for large pattern repeats.

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Typical rooms

8 ft walls, 1 door, 1 window, 10% waste, 2 coats
RoomWall areaWallpaperPaintFlooring
10 × 10 ft285 sq ft6 rolls1.8 gal110 sq ft
12 × 12 ft349 sq ft7 rolls2.2 gal158.4 sq ft
12 × 14 ft381 sq ft8 rolls2.4 gal184.8 sq ft
15 × 20 ft525 sq ft11 rolls3.3 gal330 sq ft

How the estimate works

Wall area is the room’s perimeter times the wall height, minus doors and windows. Wallpaper rolls are the wall area plus waste, divided by the coverage of one roll and rounded up. Paint is wall area times the number of coats, divided by 350 sq ft per gallon, plus waste. Flooring is the floor area plus waste.

Before you buy

  • Check the coverage printed on your wallpaper and paint; products vary, and large pattern repeats waste more paper.
  • Buy all wallpaper rolls from the same batch (lot number) so the color matches.
  • The ceiling is not included. Measure it like a floor if you are painting it.

Frequently asked questions

How many square feet does a roll of wallpaper cover?

A standard US double roll is 20.5 inches wide and 33 feet long, about 56 square feet. Pattern matching wastes some of that, so add 10% or more for patterned paper.

How much area does a gallon of paint cover?

Sherwin-Williams puts one gallon at 350 to 400 square feet per coat. This calculator uses 350 to stay on the safe side. Textured or porous walls take more.

Should I subtract doors and windows?

Yes for paint and wallpaper. The calculator takes off 20 sq ft per door and 15 sq ft per window. If your openings are much bigger, such as a patio door, count it as two doors.

How much extra flooring should I buy?

A 10% allowance covers cuts and mistakes for most straight layouts. Diagonal or herringbone layouts usually need more; follow the flooring maker’s advice.

Sources and last updated

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