About this calculator
Enter the room's length, width and wall height in metres, plus the number of doors and windows, and get the number of rolls to buy.
The calculator counts whole drops (strips of paper from ceiling to skirting), allows 10 cm for trimming, and rounds up to a whole pattern repeat if your paper has one. A standard UK roll is 0.53 m wide and 10.05 m long.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
4 m × 3 m room, plain paper
- Rolls to buy
- 6
- Strips (drops) needed
- 23
- Length of each drop
- 2.5 m
- Drops from one roll
- 4
- Wall distance to cover
- 11.9 m
A 4 m × 3 m room with 2.4 m walls needs 6 rolls of 0.53 m wide paper (23 drops).
Show the working
- Distance round the walls = 2 × (4 + 3) = 14 m, less 1 door (0.9 m each) and 1 window (1.2 m each) = 11.9 m.
- Drops = 11.9 ÷ 0.53 m roll width, rounded up = 23.
- Each drop is the wall height plus 10 cm to trim = 2.5 m, so one 10.05 m roll gives 4 drops.
- Rolls = 23 ÷ 4, rounded up = 6. Buy a spare roll for mistakes and keep all rolls from one batch number.
Same room with a 64 cm pattern repeat
- Rolls to buy
- 9
- Strips (drops) needed
- 27
- Length of each drop
- 2.56 m
- Drops from one roll
- 3
- Wall distance to cover
- 14 m
A 4 m × 3 m room with 2.4 m walls needs 9 rolls of 0.53 m wide paper (27 drops).
Show the working
- Distance round the walls = 2 × (4 + 3) = 14 m, less 0 doors (0.9 m each) and 0 windows (1.2 m each) = 14 m.
- Drops = 14 ÷ 0.53 m roll width, rounded up = 27.
- Each drop is the wall height plus 10 cm to trim, rounded up to a whole pattern repeat of 64 cm = 2.56 m, so one 10.05 m roll gives 3 drops.
- Rolls = 27 ÷ 3, rounded up = 9. Buy a spare roll for mistakes and keep all rolls from one batch number.
Large room 6 m × 5 m, 2.6 m walls
- Rolls to buy
- 11
- Strips (drops) needed
- 32
- Length of each drop
- 2.7 m
- Drops from one roll
- 3
- Wall distance to cover
- 16.6 m
A 6 m × 5 m room with 2.6 m walls needs 11 rolls of 0.53 m wide paper (32 drops).
Show the working
- Distance round the walls = 2 × (6 + 5) = 22 m, less 2 doors (0.9 m each) and 3 windows (1.2 m each) = 16.6 m.
- Drops = 16.6 ÷ 0.53 m roll width, rounded up = 32.
- Each drop is the wall height plus 10 cm to trim = 2.7 m, so one 10.05 m roll gives 3 drops.
- Rolls = 32 ÷ 3, rounded up = 11. Buy a spare roll for mistakes and keep all rolls from one batch number.
How it's worked out
The distance round the room, less the doors (0.9 m each) and windows (1.2 m each), is divided by the roll width to count the drops. Each drop is the wall height plus 10 cm to trim, rounded up to a whole pattern repeat. The number of drops one roll yields is its length divided by the drop length, rounded down. Rolls needed = drops ÷ drops per roll, rounded up.
Pattern repeat
A repeat means each strip must line up with the last, so extra paper is wasted at the top. A larger repeat wastes more. Check the label for the repeat in centimetres and for 'straight match' or 'drop match'. A drop-match pattern can need slightly more.
Buying tips
- Buy one spare roll: shades vary between batches, so buy all rolls with the same batch number
- Measure the tallest wall for the height
- For a chimney breast or feature wall, run the calculator for that wall alone
Frequently asked questions
How many rolls of wallpaper do I need?
Divide the distance round the room by the roll width to get drops, work out drops per roll from the wall height, then divide and round up.
How big is a standard wallpaper roll?
In the UK, 0.53 m wide and 10.05 m long.
What is a pattern repeat?
The distance before the pattern repeats vertically. Strips are cut to line up, which uses extra paper.
Do I subtract doors and windows?
Yes, the calculator removes a typical 0.9 m for each door and 1.2 m for each window.
How much extra should I buy?
One spare roll, from the same batch.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.