Wallpaper Roll Calculator
Calculate how many wallpaper rolls you need for a room, accounting for doors, windows, and pattern repeats.
Did this tool work for you?
How to use this calculator
Total wall area minus door (1.8 m² each) and window (1.2 m² each) deductions. Pattern repeats reduce usable roll area. Add 10% for waste and trimming.
- 1
Measure the length, width, and ceiling height of the room.
- 2
Count the number of doors and windows.
- 3
Enter the roll dimensions from the wallpaper packaging.
- 4
Enter the pattern repeat (0 for plain or non-matching wallpaper).
- 5
The calculator shows the minimum rolls needed and a buffered total.
Frequently asked questions
How does the wallpaper calculator work out the number of rolls?
It finds net wall area (perimeter × ceiling height, minus 1.8 m² per door and 1.2 m² per window), then divides by the usable area of one roll. Usable area is whole strips per roll × roll width × ceiling height. The result is rounded up to whole rolls.
How many strips come from one roll?
The tool divides the roll length by the ceiling height, plus the pattern repeat if you entered one, and rounds down. A 10 m roll with a 2.4 m ceiling gives 4 strips; with a 64 cm repeat added to each drop it gives 3.
How is pattern repeat handled?
The repeat in centimetres is added to the length of every strip, to model the extra paper needed to match the pattern. Leave it at 0 for plain or non-matching papers. The tool does not distinguish straight, drop or random matches.
What does the 10% waste figure do?
It multiplies the rolls needed by 1.1 and rounds up. The result is always at least one roll more than the base count, as 7 rolls became 8 for the default room.
Are door and window sizes adjustable?
No. Each door deducts 1.8 m² and each window 1.2 m², whatever their real size. Enter measured openings by reducing the counts or adjusting your own sums if your openings differ.
Does it work out the number of strips per wall?
No. It works from wall area, not from individual drops, so it does not count how many roll widths fit around the room. It can therefore differ from a strip-by-strip count, which is a good cross-check. Strips above doors and under windows are also not itemised.
What if my ceiling is taller than the roll?
The strip count becomes 0 and the tool falls back to the full roll area, so the answer is unreliable. Paper that short cannot cover the wall in one drop, so use a different layout or check with the supplier.
What happens if I leave a box empty or enter 0?
An emptied box counts as 0. Room length, room width, ceiling height, roll width and roll length cannot be 0, so the tool shows a message naming the field and asking for a value above 0 m. Doors, windows and pattern repeat can be 0, which means no deduction and no pattern matching.
Which units are used?
Metres for all dimensions and centimetres for pattern repeat. The room is treated as a rectangle with four walls and no alcoves.
Counting wallpaper rolls for a rectangular room
From room size to wall area
The calculator first measures how much wall there is. The perimeter of a rectangular room, twice its length plus width, times the ceiling height gives the gross wall area. It then subtracts a fixed 1.8 m² for each door and 1.2 m² for each window. What remains is the net area that paper has to cover, and it is compared against how much usable paper a roll really provides.
Why strips matter more than roll area
A roll cannot be used as a flat sheet because wallpaper hangs in full-height strips. The tool therefore counts whole strips per roll first. With a 2.4 m ceiling, a 10 m roll yields four strips and wastes the remaining 0.4 m. Adding a pattern repeat lengthens each strip and can drop the strip count, which sharply reduces the usable area of each roll.
Results for four rooms
The table lists the calculator output for four fixed rooms. The default room is 4 m by 3.5 m with one door and two windows on a 0.52 m by 10 m roll; the second repeats it with a 64 cm pattern repeat. The third is a large room on a wider roll, and the fourth a small square room, with and without a 32 cm repeat.
| Room | Net wall area | Strips per roll | Usable per roll | Rolls | With 10% buffer |
|---|---|---|---|---|---|
| 4 × 3.5 m, 2.4 m ceiling, 1 door, 2 windows, no repeat | 31.80 m² | 4 | 4.99 m² | 7 | 8 |
| Same room, 64 cm repeat | 31.80 m² | 3 | 3.74 m² | 9 | 10 |
| 5 × 4 m, 2.6 m ceiling, 2 doors, 3 windows, 0.7 × 10.05 m roll | 39.60 m² | 3 | 5.46 m² | 8 | 9 |
| 3 × 3 m, 2.5 m ceiling, 1 door, 1 window, no repeat | 27.00 m² | 4 | 5.20 m² | 6 | 7 |
| Same 3 × 3 m room, 32 cm repeat | 27.00 m² | 3 | 3.90 m² | 7 | 8 |
What the repeat does
Adding a 64 cm repeat to the default room costs two more rolls, going from 7 to 9, even though the walls have not changed. The extra length means only three strips fit on each 10 m roll instead of four. A similar jump appears in the 3 m square room, where a 32 cm repeat lifts the answer from 6 rolls to 7. If your paper has a large repeat, check the figure in the pattern details, as this can matter more than the room size.
Checking before you buy
Count the drops by hand as a cross-check: divide the room perimeter by the roll width, round up, and compare how many drops your rolls can supply. Confirm the roll width and length against the label, since the tool takes whatever you type. Buy all rolls from the same batch, and keep the buffer unless you are confident about trimming losses.
Learn more from an authoritative source:
WikipediaFence Stain Calculator
Calculate how much fence stain or paint you need based on fence size, style, and number of coats.
Mulch Calculator
Calculate how many cubic yards or cubic metres of mulch you need for a garden bed, plus bags required.
Raised Bed Soil Calculator
Calculate how much soil and compost you need to fill a raised garden bed, with mix breakdowns.
Lawn Seed Calculator
Calculate exactly how much grass seed you need based on lawn area, grass type, and seeding purpose.
Plant Spacing Calculator
Calculate how many plants fit in a garden bed using square grid or triangular offset planting patterns.
Watering Schedule Calculator
Calculate how much water your garden needs per week based on plant type, climate, and recent rainfall.
Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →