How many wallpaper rolls do I need?

Divide the wall perimeter by the roll width to find the number of drops, work out how many full drops you get from a roll given the wall height plus pattern repeat, then divide the drops by the drops per roll and round up.

Why does the pattern repeat matter?

With a patterned wallpaper, each drop has to be cut to align the pattern with its neighbour, which wastes some length at the top of each drop. A larger repeat means more waste, so it reduces how many usable drops you get from a roll.

Should I subtract doors and windows?

For a straightforward estimate, use the full perimeter, which builds in a buffer. You can deduct very large openings, but it is wise to keep the extra in case of mistakes, and to buy all rolls from the same batch for a consistent pattern.

Wallpaper Rolls Calculator

This calculator works out how many rolls of wallpaper you need to paper a room in New Zealand, taking account of the roll size and the pattern repeat that quietly increases how much you use. Wallpaper is sold by the roll, and because each roll only yields a certain number of full-height strips, or drops, the number of rolls is rarely as simple as dividing the wall area, especially with a patterned paper where length is lost at the top of each drop to line the pattern up. Get it wrong and you either run short, with the risk of a mismatched batch, or are left with costly spare rolls. The method is to divide the wall perimeter by the roll width to find how many drops you need to go around the room, then work out how many drops you get from one roll given the wall height plus the pattern repeat, and divide one by the other. You enter the wall perimeter, the wall height, the roll length and width, and the pattern repeat, and the calculator returns the number of rolls needed and the drops required. Use the full perimeter for a safe estimate, buy all rolls from the same batch for a consistent pattern, and keep any offcuts for repairs. An estimate to plan and budget your wallpapering.

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Wall perimeter (m)

Wall height (m)

Roll length (m)

Roll width (m)

Pattern repeat (m)

wallpaper rolls needed

Drops around the room31

Drops per roll4

Uses the full perimeter for a safe estimate. A larger pattern repeat means fewer drops per roll. Buy from one batch. An estimate for planning only.

How it works

The number of drops is the wall perimeter divided by the roll width, rounded up. The drops per roll is the roll length divided by the wall height plus the pattern repeat, rounded down to whole drops. The rolls needed is the drops divided by the drops per roll, rounded up.

Worked example

A room with a 16 metre perimeter and 2.4 metre walls needs 31 drops using 0.53 metre wide rolls. A 10 metre roll yields 4 drops of 2.5 metres each (2.4 plus a 0.1 metre repeat), so 31 drops needs 8 rolls.

Related calculators

Paint Quantity: paint instead.
Curtain Fabric: curtain metres.
Tile Count: tiles for a wall.
Area Calculator: areas of shapes.

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