Show the formula and working
This wallpaper calculator works out how many rolls of wallpaper you need for a room, allowing for trimming and pattern repeat, for decorators in the UK, Ireland and Europe. Enter the room size, wall height, roll size and the repeat shown on the label, and it counts the drops for you instead of guessing from area alone.
Quick answer: the wallpaper calculator divides the wall length by the roll width to find the drops, then works out how many drops one roll gives after 10 cm of trim and the pattern repeat. A 4 m by 3.5 m room with 2.4 m walls needs 8 rolls of plain 53 cm by 10.05 m paper.
What Is a Wallpaper Calculator?
A wallpaper calculator is a tool that counts how many full length strips, called drops, a room needs and how many rolls those drops can be cut from.
Our wallpaper calculator works in four stages. It finds the room perimeter, takes away any door and window widths you choose to skip, and divides by the roll width to get the number of drops. It then sets each drop at the wall height plus 10 cm of trim (5 cm top and bottom) plus one pattern repeat. Roll length divided by that drop, rounded down, gives drops per roll. Drops needed divided by drops per roll, rounded up, gives the rolls.
This drop method is more reliable than dividing wall area by the area of a roll, because the offcut at the end of every roll is too short to use. An area based wallpaper calculator can undercount by a roll or more in a typical bedroom.
How Do You Use the Wallpaper Calculator?
- Measure the room length and width and enter them in metres, or switch to feet.
- Measure the wall height from skirting to ceiling, or to the coving or picture rail if you will stop there.
- Enter the total width of doors and windows you will not paper over, or leave it at 0 for a safe estimate.
- Check the roll label and enter the roll width and length. Most UK and European rolls are 53 cm by 10.05 m, which are the defaults.
- Enter the pattern repeat in centimetres from the label, or 0 for plain or free match paper.
- Read the rolls needed and the suggested number to buy, which adds one spare roll from the same batch.
How Many Rolls of Wallpaper Do I Need for a Room?
A 4 m by 3.5 m room with 2.4 m walls needs 8 rolls of plain 53 cm by 10.05 m wallpaper, or 10 rolls if the paper has a pattern repeat.
The jump happens because a 2.4 m wall uses 2.5 m of paper per plain drop, so a 10.05 m roll gives 4 drops. Add any pattern repeat and the drop grows past 2.51 m, so the roll gives only 3 drops with a long offcut left over. That single change raises the room from 8 to 10 rolls.
Because of this, a small change in wall height or repeat can change the order by several rolls. Always run your own measurements through the wallpaper calculator rather than relying on a chart of typical rooms.
What Size Is a Standard Roll of Wallpaper in the UK?
A standard UK and European roll of wallpaper is about 53 cm wide and 10.05 m long, which covers roughly 5.3 m².
Some makers list 52 cm, and Wikipedia’s wallpaper article describes the European roll as about 52 cm by 10 m. American rolls are wider and shorter, and many murals, wide vinyls and designer papers come in 70 cm, 90 cm or even wider formats sold by the metre. Never assume: read the width and length printed on the label and enter both in the wallpaper calculator.
Wider rolls mean fewer drops and seams, but each roll is heavier to hang and the drops per roll still depend on your wall height. The wallpaper calculator accepts any roll width from 30 cm to 120 cm.
Drops per Roll by Wall Height and Pattern Repeat
The table shows drops per 10.05 m roll, and rolls for a 4 m by 3.5 m room with no deductions, all produced by the wallpaper calculator.
| Wall height | Plain (0 cm) | 26 cm repeat | 53 cm repeat | 64 cm repeat |
|---|---|---|---|---|
| 2.2 m | 4 drops, 8 rolls | 3 drops, 10 rolls | 3 drops, 10 rolls | 3 drops, 10 rolls |
| 2.4 m | 4 drops, 8 rolls | 3 drops, 10 rolls | 3 drops, 10 rolls | 3 drops, 10 rolls |
| 2.7 m | 3 drops, 10 rolls | 3 drops, 10 rolls | 3 drops, 10 rolls | 2 drops, 15 rolls |
| 3 m | 3 drops, 10 rolls | 2 drops, 15 rolls | 2 drops, 15 rolls | 2 drops, 15 rolls |
How Does Pattern Repeat Affect How Much Wallpaper You Need?
Pattern repeat adds up to one full repeat of waste to every drop, because each strip must start at the same point in the design as the one next to it.
The repeat is the vertical distance before the pattern starts again, and it is printed on the roll label with the match type. A straight match lines up across at the same height. A half drop match shifts every other strip by half a repeat. Either way, you lose some paper aligning each drop, so the wallpaper calculator adds one whole repeat per drop to stay on the safe side.
Free match and plain papers have no repeat, so enter 0. Large repeats above about 60 cm can cut a roll to 2 drops on taller walls, which is why bold designer papers often need far more rolls than the room size suggests.
Worked Example: Priya’s Patterned Bedroom
Priya is papering her 4.2 m by 3.6 m bedroom in Manchester with a floral paper that has a 53 cm straight match repeat. The walls are 2.4 m high. She will skip one 0.8 m door and a 1.0 m window, so she enters 1.8 m of openings. The roll is a standard 53 cm by 10.05 m.
- Perimeter: 2 x (4.2 m + 3.6 m) = 15.6 m, less 1.8 m of openings = 13.8 m to cover
- Drops needed: 13.8 m / 0.53 m = 27 (rounded up)
- Drop length: 2.4 m + 0.1 m trim + 0.53 m repeat = 3.03 m
- Drops per roll: 10.05 m / 3.03 m = 3 (rounded down)
- Rolls: 27 / 3 = 9 rolls, so buy 10 with one spare from the same batch
If Priya chose a plain paper instead, the wallpaper calculator gives 4 drops per roll and only 7 rolls. The pattern costs her two extra rolls, which is worth knowing before comparing prices per roll.
Tips for Buying and Hanging Wallpaper
- Check every roll has the same batch number. Graham & Brown explains that rolls from mixed batches can show small differences in colour and pattern once hung.
- Buy the spare roll at the same time. A later order may come from a different batch.
- Paint the ceiling and woodwork before papering. The ceiling paint calculator works out that paint.
- Hang lining paper first on poor walls. Lining paper is plain, so run it through the wallpaper calculator with a repeat of 0.
- For a single feature wall, divide its width by the roll width to get the drops, as in the FAQ below, then use the drops per roll the wallpaper calculator shows for your height.
- Open a window while pasting and drying, and use a stable stepladder for the top of each drop.
If you are choosing between paint and paper for a room, the paint calculator gives the litres for the same walls so you can compare both jobs.
Wallpaper Calculator FAQs
How many drops do you get from a roll of wallpaper?
A standard 10.05 m roll gives 4 drops on a 2.4 m wall with plain paper, because each drop uses about 2.5 m including trim. Add a pattern repeat or raise the wall to 2.7 m and it drops to 3.
How much wallpaper do I need for one wall?
Divide the wall width by the roll width to get the drops, rounding up. Then divide by the drops per roll for your height and repeat. A 3.5 m wide, 2.4 m high wall needs 7 drops, which is 2 rolls of plain paper.
Should I buy an extra roll of wallpaper?
Yes. The wallpaper calculator suggests one spare roll from the same batch. It covers cutting mistakes, damage and future repairs, and a roll bought later may not match the colour of the original batch.
Do you subtract doors and windows when calculating wallpaper?
You can subtract their widths, but many decorators leave them in because the strips above and below still use paper. Leaving the openings input at 0 gives a safer estimate, especially with patterned paper.
What does a half drop pattern mean?
A half drop pattern repeats diagonally, so every second strip starts half a repeat lower than its neighbour. It usually wastes more paper than a straight match. Enter the full repeat from the label into the wallpaper calculator.
How many rolls of wallpaper for a 12 x 12 ft room?
A 12 ft square room has a 48 ft (14.63 m) perimeter, so it needs 28 drops of 53 cm paper. With 8 ft (2.44 m) walls each drop is 2.54 m with trim, just too long for 4 per roll, so the wallpaper calculator gives 3 drops per roll and 10 rolls.
Checked October 2026. Sources: Graham & Brown support, Wikipedia (Wallpaper), Boråstapeter roll size guide.