Enter your room measurements and find out instantly how many wallpaper rolls you need. The calculator accounts for pattern repeat, match type and wastage. Free, no sign-up required.
How wallpaper quantity is calculated
The calculation runs in four steps:
- Number of drops: total wall length divided by roll width, rounded up. With 12 m of wall and a 0.53 m roll width that gives 23 drops.
- Drop length: ceiling height plus trim allowance (typically 10 cm). For patterned wallpaper this is rounded up to the next full pattern repeat.
- Drops per roll: roll length divided by drop length, rounded down. A 10.05 m roll yields 3 drops at 2.60 m each.
- Roll count: number of drops divided by drops per roll, rounded up.
Windows and doors are deliberately only partly deducted. Cutting around openings creates offcuts that can rarely be reused in full.
What is a pattern repeat?
The pattern repeat is the vertical distance after which the design starts again. It is printed on every roll label in centimetres.
- Free match (0 cm): no pattern, or a texture with no relation to the neighbouring drop. No additional wastage.
- Straight match: the pattern sits at the same height as the neighbouring drop. Each drop is cut to a full multiple of the repeat.
- Offset match: every second drop is shifted by half a repeat. Wastage is highest, but the result looks less striped.
The larger the repeat, the more material is lost. With a 64 cm repeat and a 2.50 m ceiling, each drop is cut to 3.20 m — 70 cm per drop becomes waste.
Estimating paste correctly
Non-woven wallpaper is hung using the paste-the-wall method: paste goes onto the wall and the dry drop is applied on top. Consumption is lower than with paper wallpaper, which has to be pasted and left to soak.
As a rule of thumb, a 200 g pack of paste covers roughly 30 m² of non-woven or 25 m² of paper wallpaper. The exact figure is on the paste packaging and depends on how absorbent the surface is. Highly absorbent walls should be primed first.
Frequently asked questions
How many rolls of wallpaper do I need for one room?
A room of 4 × 5 m with a 2.50 m ceiling has around 18 m of wall. With a standard roll of 0.53 m width and 10.05 m length and no pattern repeat, about 12 rolls are needed. With a repeat, the requirement rises by one to three rolls depending on the pattern size.
Should I deduct windows and doors?
Only partly. Do not deduct small openings at all, because cutting around them produces waste. Deduction only pays off for large areas such as a patio door or a full window front.
What is the difference between straight and offset match?
With a straight match the pattern sits level with the neighbouring drop. With an offset match every second drop is shifted by half a repeat. Offset creates more waste but avoids a striped appearance on the finished wall.
Why should all rolls come from the same batch?
Wallpaper is produced in batches. Minimal colour differences between two batches can become visible as stripes on the finished wall. The batch number is printed on the label of every roll.
How much wastage should I allow?
Around 5 percent is enough without a pattern. Allow 10 to 15 percent for a straight match, and up to 25 percent for an offset match with a large repeat. The calculator already accounts for this through the drop length.