Wallpaper calculator with pattern repeat
This wallpaper calculator tells you how many rolls to buy for a room. It counts the vertical strips (“drops”) needed to cover the wall widths, works out how many drops one roll yields once the pattern repeat and trim are allowed for, and rounds up to whole rolls plus any spares. Enter the price per roll and you also get the cost.
Paper is wasted in two places that a simple area ÷ roll area sum ignores: every drop is cut longer than the wall for trimming, and a patterned paper must be cut so the design lines up, which can throw away up to a full repeat per drop. That is why a 53 cm × 10.05 m roll that “covers 5.3 m²” rarely covers more than three drops on a 2.7 m wall — and only two when the repeat is large.
Metric and imperial sizes are both supported, including European 53 cm rolls, wide non-woven rolls and American single and double rolls. The calculation runs in your browser as you type.
How to use the Wallpaper Calculator
- Choose metric or imperial, then type the widths of the walls you are papering separated by commas (all four walls for a whole room) and the wall height.
- Pick the roll size from the list or choose “Custom size” and enter the width and length printed on the label.
- Enter the pattern repeat (on the label or the back of the sample) and the match type: straight, offset/half-drop, or free match for plain and random designs.
- Optionally deduct large openings such as patio doors in m² or ft². Leave ordinary doors and windows at 0 — the drops around them are still cut full length.
- Add the price per roll and the number of spare rolls, then read the drops, drops per roll, rolls to buy and cost. Copy or share the summary.
Wallpaper Calculator features
Drop-based counting
Counts strips the way a decorator does — wall width ÷ roll width — rather than dividing areas, so partial drops are never forgotten.
Pattern repeat and match types
Each drop is rounded up to whole repeats for straight match and gets an extra half repeat for offset (half-drop) papers.
Roll presets worldwide
53 cm, 70 cm and 1.06 m European rolls, US 20.5 in single and 27 in double rolls, UK 21 in rolls, or any custom size.
Trim allowance you control
The 10 cm (4 in) cut at top and bottom is included and adjustable for uneven ceilings.
Spare rolls and cost
Add a batch-matched spare and get the total cost in ₹, $, £ or €.
Transparent working
A step table shows every intermediate number so you can check it against the shop’s advice.
How the rolls are calculated
The jump from 8 to 12 rolls for the same room shows why the repeat must never be ignored. If you are between two roll sizes, the wider or longer roll usually wins on cost per drop.
- Drops needed = total wall width ÷ roll width, rounded up. 12 m of wall ÷ 0.53 m = 22.6 → 23 drops.
- Drop length = wall height + trim allowance, rounded up to a whole number of pattern repeats. 2.7 m + 0.10 m = 2.8 m; with a 90 cm repeat that becomes 3.6 m. Offset-match papers add half a repeat.
- Drops per roll = roll length ÷ drop length, rounded down. 10.05 m ÷ 2.8 m = 3 (or 2 with the 90 cm repeat).
- Rolls = drops needed ÷ drops per roll, rounded up, plus spares. 23 ÷ 3 = 7.7 → 8 rolls, or 12 rolls with the large repeat.
Roll sizes and what they cover
American papers are usually priced per single roll but sold as double rolls — enter the double-roll size so the count matches what you can actually buy.
| Roll | Size | Area | Drops on a 2.7 m / 9 ft wall (plain) |
|---|---|---|---|
| European / Indian standard | 53 cm × 10.05 m | 5.3 m² | 3 |
| Wide non-woven | 1.06 m × 10.05 m | 10.6 m² | 3 (each twice as wide) |
| US single roll | 20.5 in × 33 ft | 56 ft² | 3 |
| US double roll | 27 in × 27 ft | 61 ft² | 2 (3 on an 8 ft wall) |
| UK standard | 21 in × 20 ft (53 cm × 6.1 m) | 35 ft² | 2 |
Buying tips
- Buy all rolls from the same batch number; colours vary between batches and the spare roll should match too.
- For a feature wall only, enter just that wall’s width. For a border, divide the room perimeter by the border roll length instead.
- Papering around a bay window or chimney breast adds drops: enter each face as a separate width.
- Planning paint for the other walls? Use the paint calculator; for floors see the flooring calculator.
Wallpaper Calculator FAQ
How many rolls of wallpaper do I need for a 10 × 12 ft room?
The perimeter is 44 ft. With US double rolls (27 in wide) that is 20 drops; on 8 ft walls a 27 ft roll gives 3 drops, so you need 7 rolls plus a spare. The wallpaper calculator shows the same working for your own sizes and repeat.
What is pattern repeat and why does it matter?
It is the vertical distance before the design repeats, printed on the label (e.g. 64 cm). Each drop must start at the same point in the design, so drops are cut in whole repeats and the offcuts are waste. Large repeats can add 20–50% to the rolls needed.
What is the difference between straight and offset match?
In a straight match the design lines up at the same height on every drop. In an offset (half-drop) match, every second drop is shifted by half a repeat, which wastes a little more paper — the calculator adds half a repeat per drop for it.
Should I subtract doors and windows?
Usually not. The strips either side of a door are cut full length and the piece above it comes from the offcut, so deducting them often leaves you short. Only deduct very large openings such as sliding doors.
Why do I need a spare roll?
Repairs years later need paper from the same batch, and a miscut during hanging can cost a whole drop. One spare roll is cheap insurance.
Does this work for lining paper and peel-and-stick?
Yes. Lining paper is a free-match paper with 0 repeat; peel-and-stick rolls are often 50 cm × 3 m or 20 in × 18 ft — choose Custom size and enter the roll dimensions.