🧻 Wallpaper Calculator

Enter your wall size and roll dimensions to find out how many rolls of wallpaper you need — accounting for pattern repeat, waste, and total cost.

Walls
ft Add up the width of every wall you're covering (the room's perimeter, minus any walls you skip).
ft
Wallpaper roll
in
ft
in Enter 0 for a plain or random-match paper. Otherwise use the repeat printed on the roll label.
$
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How to calculate how much wallpaper you need

Wallpaper is hung in full-height vertical strips, so the math is about strips, not raw square footage. You work out how many strips you can cut from one roll, how many strips it takes to go around the room, and divide. Pattern repeat eats into each roll because you have to trim strips to line the design up — this calculator factors that in for you.

The method, step by step

1. Strips needed = total wall width ÷ roll width (rounded up).
2. Usable strip length = wall height + pattern repeat allowance (so the pattern lines up).
3. Strips per roll = roll length ÷ usable strip length (rounded down).
4. Rolls = strips needed ÷ strips per roll (rounded up).

Why pattern repeat costs you rolls

With a plain paper, every inch of the roll is usable. But with a large pattern repeat, each strip has to start at the same point in the design, so you trim and discard up to one repeat's worth of paper per strip. A big repeat can easily push you from 5 rolls up to 6 or 7 — always check the repeat on the label before buying.

Standard wallpaper roll sizes

Roll type Typical size Notes
🇺🇸 US single roll~21 in × 33 ftOften sold as double rolls
🇬🇧 UK / Euro roll~53 cm × 10 mThe common standard
🖼️ Peel & stickVaries widelyCheck the specific product

Buy a spare from the same batch

Always round up to whole rolls and grab at least one extra, ideally with the same batch (lot) number — colors shift slightly between print runs, so a later top-up roll may not match the walls you've already hung.