Wallpaper Calculator

Use it when your task matches one of these common needs: Estimate rolls for a bedroom, office, or powder room. Subtract common doors and windows from wall area. It works best when you already know the values, dates, units, or settings the page asks for.

In plain language: The calculator finds wall area from room perimeter and height, subtracts estimated doors and windows, adds waste, divides by roll coverage, and rounds up. The examples on the page are there so you can compare your inputs with a filled-out calculation before copying the answer.

Room length and width: the two pairs of walls used to estimate total wall area from room perimeter. Doors and windows: standard openings subtracted from wall area before waste is added. Roll coverage: usable square feet one roll covers; use the product label because pattern repeat can reduce it. Waste percent: extra wallpaper for trimming, matching patterns, damaged strips, and mistakes.

Read the headline estimate first, then check the material, waste, coverage, and unit lines. For project tools, the supporting lines are often the difference between a rough idea and a list you can actually shop from.

Wallpaper needs can change with pattern repeat, usable roll yield, accent walls, odd wall shapes, trimming, damaged strips, and dye lots. Also check that you used the right unit, date, scale, or mode because small input changes can change the result.

Waste percent is extra wallpaper added before the roll count is rounded up. It covers the pieces you cut off at the ceiling and baseboard, strips that need to shift so the pattern lines up, damaged pieces, and small measuring mistakes. If the wall math says you need 300 square feet and you enter 10% waste, the calculator plans for 330 square feet before dividing by roll coverage.

Use 10% as a simple starting point for plain, random-match, or easy peel-and-stick wallpaper. Use about 15% when there is a normal pattern repeat or several corners and openings. Use 20% or more for large pattern repeats, drop matches, older uneven walls, or if you want spare paper for repairs. The product label and installer advice should win when they give a specific number.

Roll coverage is the usable square feet from one roll or bolt. Do not guess this from the roll size if the product page already gives coverage, because pattern repeat can lower the amount that actually lands on the wall. Some products are priced as single rolls but shipped as double rolls, so check whether the coverage number belongs to the roll you are buying.

A repeating pattern has to line up from strip to strip. That means a strip may need to be cut longer than the wall height so the design starts in the right place. The extra cut-off part is not a mistake; it is the cost of making the pattern match instead of looking shifted.

For a rough estimate, subtracting standard doors and windows keeps the roll count from getting too high. For peel-and-stick or patterned wallpaper, some stores advise not subtracting openings because you still cut around them and may need full-height strips. If you are close to the next roll, it is usually safer to round up.

Wallpaper can have tiny color differences between print runs. The lot, run, or batch number helps you buy rolls printed together. If you buy more later from a different lot, the pattern may be correct but the color can still look slightly off on the wall.

No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.