Wallcoverings
Wallpaper rolls from height, perimeter, roll size and pattern repeat
- where
- length of each drop (m); H + t for a free match
- wall height to paper (m)
- trimming allowance (m)
- pattern repeat (m)
- half-drop match (1 yes, 0 no)
- drops per roll
- roll length (m)
- drops needed
- width to paper (m)
- roll width (m)
- rolls needed
Explain this equation
Works out how many rolls of wallpaper a room needs, allowing for the pattern repeat.
Each drop must start at the same point in the pattern, so its length is the wall height plus trimming, rounded up to a whole number of repeats. A half-drop pattern wastes up to half a repeat more. Only whole drops come out of a roll, so the roll length is divided by the drop and rounded down. The number of drops is the width to cover divided by the roll width, rounded up, and the rolls needed is drops divided by drops per roll, rounded up.
Whole-number rounding at each step: up for drops and repeats, down for drops per roll.
Sense check: 2.4 m walls with a 53 cm repeat give 2.65 m drops, three per 10 m roll; a 14 m perimeter needs 27 drops, so 9 rolls.
Watch out: buy all rolls from one batch, plus a spare. Large repeats can waste a lot of paper.
Works out wallpaper rolls by counting full-length drops: drop length allowing for the pattern repeat, drops per roll, and drops round the room.
Enter your values to see the result.
Good to know
The standard Euro roll is 10.05 × 0.53 m (some UK papers 0.52 m; Farrow & Ball 10 × 0.53 m). Each drop is the wall height plus trimming (about 50 mm top and bottom), rounded up to a whole number of repeats so the pattern lines up; a half-drop or offset match wastes about half a repeat more per drop. Offcuts are not counted, so going round doors and windows the count is a little generous, which is how most manufacturers’ charts work. Check: Farrow & Ball quote 4 drops per roll for stripes in a 2.4 m room, and about 5 drops (2 rolls) for a 2.5 m wide wall.
Common mistake
Working from area alone. Area ÷ roll area ignores the waste at the end of every roll and the repeat, and usually comes up a roll or two short.
Limits
Straight walls of one height. For walls of different heights or stairwells, run each wall separately. Check the batch number on every roll.
Sources
- A.S. Création, roll calculator (standard Euro roll 10.05 m × 0.53 m; add about 5 cm to the height; buy a spare roll)
- Farrow & Ball, Calculating wallpaper quantities (rolls 10 m × 53 cm; 2.4 m room: 3 drops per roll for small repeats, 4 for stripes, 2 for large repeats; 2.5 m wide wall needs about 5 drops, roughly 2 rolls; add one more roll)
- Christopher Farr Cloth, How to calculate wallpaper quantities (drops = width ÷ paper width rounded up; drop = repeats × repeat height with an extra repeat; half-drop adds half a repeat)
- Graham & Brown, How to measure your room (allow about 10% extra; straight and offset match; repeat example 64/32 cm)
- Practical DIY, Estimating the number of rolls of wallpaper (standard UK roll 0.52 m × 10.05 m; larger repeats waste more)
- BS 8000-12 Workmanship on construction sites. Code of practice for decorative wallcoverings and painting
Results are calculations from the published methods and figures shown, and depend on the data you enter. Coverage depends on the product, surface and application. Always follow the paint and wallcovering manufacturers’ data sheets and BS 6150 / BS 8000-12. Check prices and VAT with your own records and HMRC.