Key takeaways
- Count whole strips rather than dividing square feet, because a roll only yields whole strips.
- A bigger pattern repeat means fewer strips per roll, so more rolls.
- Use your roll's own label, as sizes vary and single and double rolls differ.
Enter the room's size and the width, length and pattern repeat on your roll's label. The defaults use a common US double roll size, so change them to match your product.
How the calculator works
- Strips: room perimeter ÷ roll width, rounded up
- Strip length: wall height + one pattern repeat
- Strips per roll: roll length ÷ strip length, rounded down
- Rolls: strips ÷ strips per roll, rounded up
This is our own method. Many guides divide area by a roll's coverage, but that can come up short, because leftover pieces of a roll may be too short for a full strip.
We don't subtract doors and windows, which leaves you some spare for mistakes and later repairs.
Worked example
A 12 × 12 foot room with 8-foot walls, using 20.5-inch wide, 33-foot long rolls with an 18-inch repeat:
- Strips: 576 ÷ 20.5 = 28.1, so 29 strips
- Strip length: 96 + 18 = 114 inches
- Per roll: 396 ÷ 114 = 3.47, so 3 strips
- Rolls: 29 ÷ 3 = 9.7, so 10 rolls
What pattern repeat does
For the same room:
| Pattern repeat | Strip length | Strips per roll | Rolls |
|---|---|---|---|
| None | 96 in | 4 | 8 |
| 6 in | 102 in | 3 | 10 |
| 12 in | 108 in | 3 | 10 |
| 18 in | 114 in | 3 | 10 |
| 24 in | 120 in | 3 | 10 |
| 36 in | 132 in | 3 | 10 |
The jump comes when a repeat costs you a whole strip per roll. So the first few inches of repeat here cost 2 extra rolls, and then nothing changes until strips no longer fit.
Read the label
- Single or double rolls: retailers commonly describe a US double roll as about 20.5 inches wide and 33 feet long, for about 56 square feet. Prices are sometimes per single roll, while sales are by the double roll, so check.
- Coverage: retailers' guides say actual usable coverage can be well under the stated figure once pattern matching is included.
- Batch: keep all your rolls from one batch or dye lot where possible, as colors can differ. Check the batch number before you start.
We read these sizes in retailers' guides rather than a maker's standard, so your label comes first.
Before you strip old walls
In a home built before 1978, surfaces under old paper may have lead paint. Read about lead before you scrape or sand. Old patching compound can also contain asbestos, as our drywall guide explains.
Frequently asked questions
How many rolls of wallpaper do I need?
Work out the number of strips, then how many full strips fit on one roll. For a 12 × 12 room with 8-foot walls and an 18-inch repeat, that's about 10 rolls of the size above.
What is pattern repeat?
It's the distance before a pattern begins again. Each strip has to line up, so you lose some length.
Can I subtract doors and windows?
You can, but it's risky with a pattern, as cutoffs around openings are often unusable. We leave them in.
Sources
We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.
- JC Licht: How much wallpaper do I need? (a retailer's guide)
- DecoratorsBest: Wallpaper guide (a retailer's guide)