Wallpaper Calculator

How many rolls to buy, counted strip by strip the way paperhangers do it. Unlike an area estimate, this accounts for pattern repeat and the leftover at the end of each roll.

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rolls
Strips needed–
Strip length incl. trim and repeat–
Full strips per roll–

    How rolls are counted

    Wallpaper goes up in vertical strips, so area alone undercounts. First, each strip is the wall height plus about 4" for trimming at top and bottom. With a pattern, round that up to a whole number of repeats so the next strip matches. A half-drop match wastes another half repeat on average.

    strips = ⌈wall width ÷ roll width⌉ · per roll = ⌊roll length ÷ strip⌋ · rolls = ⌈strips ÷ per roll⌉

    Doors and windows aren't subtracted. The partial strips above and below them use most of a strip anyway, and the spare covers mistakes.

    Buy one extra roll

    Rolls from different print runs (batch or lot numbers) can differ slightly in color. Buy all rolls from one batch, plus one spare. Reordering later rarely matches.

    Questions

    What is a pattern repeat?

    The vertical distance before the design repeats. It is printed on the roll label, usually 0–25". Larger repeats waste more paper per strip.

    Straight vs half-drop match?

    In a straight match the design lines up across strips at the same height. In a half-drop every other strip is shifted down half a repeat, which uses more paper.