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Wallpaper Calculator

Estimate wallpaper rolls and cost from room perimeter, wall height, roll size and waste.

Your estimate

Enter measurements, then calculate.

Planning estimate only. Confirm packaging, coverage, site conditions, and local building requirements before purchasing.

How to measure

Measure the full perimeter of the walls to be covered, excluding walls that will not receive wallpaper.
Measure wall height from finished floor to ceiling or to the planned stopping line.
Check the roll width and roll length printed on the product label, especially for imported wallpaper.
Identify pattern repeat, half-drop designs and feature walls before choosing a waste allowance.

Input guide

Room perimeter is used instead of floor length and width because wallpaper is installed as vertical strips around walls.
Roll width is entered in centimetres or inches. Standard widths vary by country and product line.
Roll length is entered in metres or feet and determines how many full-height strips can be cut from each roll.
Waste should be higher for large pattern repeats, half-drop matching, sloped ceilings or many openings.

Formula

Rolls = required strips ÷ strips available per roll × (1 + waste)

The calculator divides room perimeter by roll width to estimate how many vertical strips are needed.

It then divides roll length by wall height to estimate how many full strips each roll can provide.

Waste is added for pattern matching and trimming, then the result rounds up to whole rolls.

Worked example: Bedroom wallpaper with standard rolls

A room perimeter of 13 m and wall height of 2.7 m needs vertical strips around the walls.
With 53 cm roll width, 13 ÷ 0.53 = 24.5, so 25 strips are needed.
A 10 m roll can provide 3 full strips of 2.7 m height.
25 ÷ 3 = 8.34 rolls; with 10% waste the estimate rounds up to 10 rolls.

If each roll costs 36 USD, the wallpaper estimate is 10 rolls and 360 USD before paste, tools or installation.

Buying advice

Buy all rolls from the same batch number to reduce color and pattern variation.
Review pattern repeat before ordering; large repeats can require much more waste than plain wallpaper.
Keep one spare roll for repairs because exact wallpaper designs are often discontinued.

Common mistakes

Using floor area instead of wall perimeter and height
Ignoring pattern repeat or half-drop matching
Subtracting every window and then lacking matching material around reveals
Mixing rolls from different batch numbers
Forgetting that short off-cuts may not be usable on full-height walls

Pattern repeat controls usable drops

Wallpaper is normally installed as full-height strips, or drops, rather than purchased only by total wall area. A straight match, offset match, large repeat, or motif that must align can shorten the usable length of each roll and increase offcuts.

Read the repeat and match symbols on the exact roll label. When the design has a large repeat, calculate how many full matched drops one roll produces; two rolls with the same dimensions can therefore cover different numbers of wall strips.

Check every roll label before opening

Match the design number, colorway, batch or dye-lot number, roll width, roll length, and pattern repeat.
Confirm whether the product is sold as a single roll, double roll, bolt, mural panel set, or custom length.
Inspect rolls for shipping damage while they can still be returned under the seller’s policy.
Keep one unopened roll when practical for future repairs and record the label information.
Add paste, primer, liner, and trimming tools separately because roll count does not estimate them.

Openings do not always save a full strip

A door or window may reduce pasted area, but installation often still requires a full drop that is cut around the opening so the pattern stays aligned. Small openings should therefore not automatically be subtracted as if their area could be reused elsewhere.

The calculator cannot assess wall moisture, surface preparation, seam placement, pattern direction, or compatibility with bathrooms and kitchens. Follow the wallcovering and adhesive instructions, especially for textured, recently plastered, or previously painted walls.

Frequently asked questions

Should I subtract windows and doors?

For simple estimates, do not subtract small openings. Pattern matching and trimming often use the apparent saving.

How much waste should wallpaper have?

Use 10% for plain or small-repeat wallpaper and 15–25% for large repeats, half-drop designs or complex walls.

Why does the calculator use perimeter?

Wallpaper is installed in strips around the room, so perimeter and wall height are more useful than floor area.

What is pattern repeat?

Pattern repeat is the vertical distance before a design repeats. Larger repeats can waste more material when matching strips.

Can I calculate one feature wall?

Yes. Enter the feature wall width as the perimeter and the wall height as normal.