Show the formula and working
This wallpaper pattern repeat calculator works out how long to cut each drop of patterned wallpaper, how many drops you get from a roll and how many rolls to buy once the pattern repeat and match are taken into account. It is built for UK and European rolls of about 10 m by 0.53 m, works for free, straight and half drop matches, and shows how many extra rolls the pattern costs compared with a plain paper.
Quick answer: Add 10 cm trim to the wall height, round up to whole pattern repeats, then count drops per roll. With 2.4 m walls and a 64 cm straight match, each drop is 2.56 m and a 10.05 m roll gives 3 drops. The wallpaper pattern repeat calculator shows 9 rolls for a 14 m room.
What Is a Wallpaper Pattern Repeat Calculator?
A wallpaper pattern repeat calculator is a tool that adjusts a roll count for the extra paper lost when lining up a repeating pattern. The pattern repeat is the distance down the roll before the design starts again, and it is printed on the roll label. The formula in plain words: drop length = wall height + trim, rounded up to a whole number of repeats; drops per roll = roll length / drop length, rounded down; drops needed = wall width / roll width, rounded up; rolls = drops needed / drops per roll, rounded up.
For a half drop match, each new drop starts half a repeat further down the pattern, so the calculator also allows half a repeat between drops cut from the same roll. The Wikipedia article on wallpaper describes this offset with a 610 mm repeat, where the next piece starts 300 mm down the pattern.
How Do You Use the Wallpaper Pattern Repeat Calculator?
- Enter the Total width of walls you are papering and the Wall height.
- Choose the Pattern match shown on the roll label.
- Enter the Pattern repeat in centimetres and the Trim allowance per drop.
- Check the Roll length and Roll width on the label.
- Optionally enter the Width of doors to skip, or leave it at 0 to be safe.
- Read the rolls needed and the length to cut each drop, then open “Show the formula and working” to see each step.
What Is the Difference Between Straight Match and Half Drop?
A straight match repeats the pattern at the same height across every drop, so each drop starts at the same point in the design. A half drop (offset) match repeats the design half a repeat lower on every other drop, so the pattern runs diagonally across the wall. Free match papers, such as plain textures and stripes, have no pattern to line up at all. Half drop papers can waste more, especially on tall walls with large repeats.
How Much Extra Wallpaper Do You Need for a Pattern Repeat?
A pattern repeat usually adds one or two rolls to a typical room, because each drop is cut to a whole number of repeats instead of the wall height. The table shows a 53 cm repeat on 10.05 m by 0.53 m rolls for a room 14 m round.
| Wall height | Free match drop and drops per roll | Straight match drop and drops per roll | Half drop, drops per roll | Rolls: free, straight, half drop |
|---|---|---|---|---|
| 2.2 m | 2.30 m, 4 | 2.65 m, 3 | 3 | 7, 9, 9 |
| 2.4 m | 2.50 m, 4 | 2.65 m, 3 | 3 | 7, 9, 9 |
| 2.5 m | 2.60 m, 3 | 2.65 m, 3 | 3 | 9, 9, 9 |
| 2.7 m | 2.80 m, 3 | 3.18 m, 3 | 2 | 9, 9, 14 |
| 3.0 m | 3.10 m, 3 | 3.18 m, 3 | 2 | 9, 9, 14 |
The jump for half drop at 2.7 m comes from the half repeat lost between drops. Cutting alternate drops from two rolls can sometimes save it, but buying the higher figure avoids running short. For plain papers, the wallpaper calculator gives a quick roll count, and the lining paper calculator covers lining first.
Where Do I Find the Pattern Repeat on a Wallpaper Roll?
The pattern repeat and match type are printed on the roll label or the sample, usually as a distance in centimetres next to a set of standard symbols for straight match, offset match and free match. Some labels show the offset as a fraction, such as 53/26.5 cm for a half drop with a 53 cm repeat. If the label is missing, measure from one point in the design down the roll to where it next appears.
Should I Buy Extra Rolls of Patterned Wallpaper?
Buy one extra roll beyond the calculated figure for patterned papers if you can, and check every roll has the same batch number. Rolls from different batches can differ slightly in colour, which shows on a wall. A spare roll also covers mistakes when matching around windows and corners. Hang the first drop against a true vertical line marked with a plumb bob or spirit level, because the pattern makes any lean easy to see. The paint and decorating calculators hub has tools for the rest of the room.
Worked Example: 64 cm Straight Match in a 4 m by 3 m Room
Example: a bedroom 4 m by 3 m is 14 m round, with 2.4 m walls. The wallpaper has a 64 cm straight match, and the rolls are 10.05 m by 0.53 m. Each drop gets 10 cm of trim. These are the calculator’s default inputs.
- Drop length: 2.4 m + 0.1 m = 2.5 m, rounded up to whole 64 cm repeats: 4 x 0.64 m = 2.56 m.
- Drops per roll: 10.05 m / 2.56 m = 3.9, so 3 whole drops.
- Drops needed: 14 m / 0.53 m = 26.4, so 27 drops.
- Rolls: 27 / 3 = 9 rolls.
With no pattern to match, each roll would give 4 drops of 2.5 m and the room would need 7 rolls, so the pattern adds 2 rolls.
Wallpaper Pattern Repeat Calculator FAQs
How do you calculate wallpaper with a pattern repeat?
Add trim to the wall height, then round up to a whole number of pattern repeats to get the drop length. Divide the roll length by that drop, rounded down, and divide the number of drops you need by it. Round the rolls up.
What does a 53 cm pattern repeat mean?
It means the design repeats every 53 cm down the roll. Every drop has to start at the same point in the design, so drops are cut in steps of 53 cm. On a 2.4 m wall with 10 cm trim, each drop is cut at 2.65 m.
Does half drop wallpaper need more rolls?
Often, yes. Each new drop starts half a repeat lower in the design, so some paper is lost between drops cut from the same roll. On low walls it may make no difference, but on taller walls with large repeats it can add several rolls.
How much trim should I allow per drop?
About 10 cm per drop is usual, roughly 5 cm at the ceiling and 5 cm at the skirting, to allow for uneven ceilings and trimming. Increase it for very uneven ceilings, coving or old houses where the walls are out of square.
Can I use offcuts from patterned wallpaper?
Offcuts can be used above doors, below windows and above radiators, where short drops are needed. The calculator ignores them to be safe, so the roll count already gives you a little spare paper for those small areas.
Do I need to match the pattern at the corners?
You cannot keep a perfect match round an internal corner, so most decorators start from the focal wall and hide the mismatch in the least noticeable corner, often behind the door. Plan the first drop before cutting any paper.
Checked October 2026. Sources: Wikipedia: Wallpaper (pattern repeat, offset example, European roll about 52 cm by 10 m). Roll size, repeat and trim defaults are editable examples.