Too little wallpaper is frustrating, too much costs money. If you do the maths properly before buying, you will almost always order the right amount. The calculation depends on three values: the room perimeter, the room height and the pattern repeat of the wallpaper. This guide shows step by step how to work out the number of rolls – with a complete worked example for narrow and wide rolls.

If you are in a hurry, our wallpaper calculator does the maths for you. The guide below explains what it calculates – and what to watch out for with patterned wallpaper.

1. Measure the room perimeter and height

Measure every wall you want to paper at mid-height and add the lengths together. For a rectangular room the formula is:

Perimeter = 2 × (length + width)

Measure the room height from the top of the skirting board to the ceiling. In older buildings it is worth measuring in several places – ceilings are rarely the same height everywhere. Use the largest value.

2. Windows and doors: usually do not deduct them

In normal living spaces you do not deduct windows and doors. The offcuts created around them usually cancel out the area you save. Only with large glass areas – floor-to-ceiling windows, patio doors, glass fronts – is it worth deducting the strips that are not needed there.

3. Determine the strip length – this is where the pattern repeat matters

Every strip needs a little extra for trimming: about 5 cm at the top and 5 cm at the bottom. The strip length is therefore room height + 10 cm.

For plain wallpapers and textures without a repeat, that is already the final strip length.

With patterned wallpaper, neighbouring strips must be hung so that the pattern continues. The distance after which the pattern repeats is called the pattern repeat. It is printed on the label and in the product description. With a straight match, every strip starts at the same point of the pattern – so the strip length is rounded up to full repeats. With an offset (drop) match, every second strip is shifted by half a repeat; as a rule of thumb, allow an extra half repeat per strip.

4. Strips per roll and number of strips

Our rolls are 10.05 m long and, depending on the collection, 0.53 m or 1.06 m wide. This gives you two simple calculations:

  • Strips per roll = 10.05 m ÷ strip length – always round down, because a partial piece does not make a full strip.
  • Strips needed = perimeter ÷ roll width – always round up.
  • Rolls = strips needed ÷ strips per roll – again round up.

Worked example: room 4.00 × 3.50 m, room height 2.40 m

Perimeter: 2 × (4.00 + 3.50) = 15.00 m. Strip length without repeat: 2.40 + 0.10 = 2.50 m.

Case Strip length Strips per roll Strips in total Rolls
0.53 m wide, no repeat 2.50 m 10.05 ÷ 2.50 = 4 15.00 ÷ 0.53 = 29 8
0.53 m wide, 64 cm repeat (straight match) 4 × 0.64 = 2.56 m 10.05 ÷ 2.56 = 3 29 10
1.06 m wide, no repeat 2.50 m 4 15.00 ÷ 1.06 = 15 4

The example shows why the pattern repeat matters so much: in the same room, 8 rolls suddenly become 10. The strip length of 2.56 m is only a few centimetres longer than 2.50 m – but four such strips no longer fit on a 10.05 m roll. Always calculate patterned wallpaper with the actual repeat.

5. One spare roll – from the same batch

Order at least one roll more than the calculation shows. The reason is not only waste: wallpaper is printed in batches, and the shade can differ slightly between two batches. The batch number is printed on the label. Rolls you reorder later may come from a different batch – and on the wall that shows immediately.

The spare roll is not wasted money either: unopened, unused rolls can be returned within 15 days. You will find the conditions in our return policy.

Narrow or wide roll?

Wide rolls (1.06 m) mean half as many seams and go up faster on large, smooth walls. Narrow rolls (0.53 m) are easier to handle, especially on your own, under sloping ceilings and in rooms with many corners, windows and sockets. We explain the difference between non-woven, paper and glass fibre wallcoverings in detail in our wallpaper types comparison.

Frequently asked questions

Do I need to include the ceiling?

Only if you are papering the ceiling as well. In that case calculate the ceiling separately: the room length is the strip length (plus 10 cm), and the room width divided by the roll width gives the number of strips.

What if only one wall is being papered?

Then the "perimeter" is simply the width of that one wall. With feature walls and large pattern repeats the exact calculation is especially worthwhile, because one strip more or less can mean a whole roll.

Where do I find the pattern repeat?

On the roll label and in the product description. If no repeat or "0 cm" is given, the wallpaper has no pattern match – you can calculate with the plain strip length.

Can someone do the calculation for me?

Yes. Use the wallpaper calculator or send us your room dimensions via WhatsApp at +49 178 265 93 11 – we are happy to check the quantity for the wallpaper you have chosen.