One Wall Wallpaper Calculator
Estimate the wallpaper rolls for a single wall, with pattern repeat and a trim allowance.
Calculator
Free, runs entirely in your browser, and your numbers never leave your device. Results are estimates for planning only.
What this calculator does
Papering one wall — a feature wall behind a bed or sofa — needs far fewer rolls than a whole room. This tool counts the full-height strips for a single wall, works out how many come from one roll once the pattern is matched, and adds a trim allowance.
How to use it
- Enter just the one wall's width and its height.
- Enter the roll width and length and the pattern repeat from the label.
- Keep a 10–15% allowance for trimming and pattern matching, then read the rolls.
The formula
Drops = ⌈wall width ÷ roll width⌉. Cut length = ⌈wall height ÷ repeat⌉ × repeat (or wall height if no repeat). Rolls = ⌈drops ÷ (roll length ÷ cut length)⌉ × (1 + waste%).
Example calculation
A single 12 ft wide, 9 ft tall wall with 20.5-in × 33-ft plain rolls and a 10% allowance:
- Roll width: 20.5 in ≈ 1.71 ft
- Drops: ⌈12 ÷ 1.71⌉ = 8 strips
- Drops per roll: ⌊33 ÷ 9⌋ = 3
- Rolls: ⌈8 ÷ 3⌉ = 3, ×1.10 ≈ 3 rolls
Result: About 3 rolls — buy 3 and keep the offcuts for repairs.
Buying and planning tips
- Order one extra roll from the same batch; a feature wall is hard to patch with a new lot.
- A plain or random-match paper wastes the least on a single wall.
- Check the wall is square; out-of-plumb corners need a little extra trim.
Common mistakes to avoid
- Entering the whole room's wall width instead of the single feature wall.
- Setting the pattern repeat to 0 on a paper that actually repeats.
- Buying exactly the calculated rolls with no spare for mistakes.
Assumptions and limits
- Only the single wall you enter is estimated.
- A 10–15% allowance covers trimming and pattern matching.
- Roll dimensions vary by brand — always enter what is on your roll.
Frequently asked questions
How many rolls of wallpaper for one wall?
Count the full-height strips the wall needs, divide by the usable strips per roll, and add a trim allowance. A 12×9 ft wall with standard rolls usually needs about 3 rolls.
Does a feature wall need a pattern repeat allowance?
Yes, if the paper has a repeat. Each strip is cut to a whole repeat so the pattern lines up, which uses a bit more paper.
Should I buy an extra roll for one wall?
It is wise. Patching a feature wall later with a different batch rarely matches, so one spare from the same lot is good insurance.
What if my wall is not perfectly square?
Older walls are often out of plumb. Add a little to the trim allowance and plan to scribe the first and last strips to the corners.
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