Wallpaper Calculator

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Find out how many rolls of wallpaper you need — enter your wall size, roll dimensions and pattern repeat to get rolls, drops and total wall area instantly.

m
m
m
cm
m
cm
Rolls needed – rolls
Total wall area –
Number of drops –
Drops per roll –
Each drop adds one pattern repeat for matching. Each door or window removes roughly one drop. Always buy from the same batch and keep a spare roll — results are rounded up.

About Wallpaper Calculator

The wallpaper calculator estimates how many rolls you need to paper a room. Describe the walls either as a total width and height or as a room perimeter, add the roll’s width and length plus the pattern repeat, and it returns the rolls to buy along with the total wall area.

The math works in “drops” — the floor-to-ceiling strips cut from each roll. Every drop is lengthened by one pattern repeat so motifs align from strip to strip, and the calculator shows both the number of drops your walls need and how many drops one roll yields. Each door or window you declare removes roughly one drop.

Results are rounded up, and it is standard practice to buy all rolls from the same batch — plus a spare — because dye lots vary subtly between print runs. This free browser tool makes it painless to re-run the numbers for wallpapers with different repeats before you commit.

How to use Wallpaper Calculator

  1. Choose metric or imperial units and how you will describe the walls: width and height, or room perimeter.
  2. Enter the wall measurements and height.
  3. Add the roll width, roll length and the wallpaper’s pattern repeat.
  4. Enter the number of doors and windows.
  5. Read the rolls needed, total wall area, number of drops and drops per roll.

Frequently asked questions

A drop is one vertical strip cut to the wall height. The calculator divides your total wall width by the roll width to count drops, then works out how many full drops each roll provides.

Each drop must start at the same point in the motif to align with its neighbor, so one repeat length is added per drop. Large repeats can add a surprising amount — the calculator accounts for it automatically.

Each opening you enter removes roughly one drop from the total, a practical rule of thumb that reflects the strips you will not need to hang across those areas.

Rolls from different print batches can differ slightly in color. Buying everything from one batch, plus a spare roll for mistakes and future repairs, avoids a visible mismatch on the wall.

Either works. Use the perimeter mode for papering a whole room in one go, or the width-and-height mode when covering a single feature wall or a specific stretch of wall.
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