Wallpaper Calculator
Work out exactly how many rolls of wallpaper and how much paste you need for a room or accent wall, accounting for pattern repeat and roll size. Add your own prices for a full cost estimate — nothing here uses a stale national average.
How this calculator works
The calculator works out how many full-height strips fit on one roll after pattern-repeat loss, how many strips the room needs, then how many rolls that takes:
usable_strip_length = roll_length − (pattern_repeat_in / 12) strips_per_roll = floor(usable_strip_length / wall_height) strips_needed = ceil(total_wall_width / roll_width) rolls = ceil(strips_needed / strips_per_roll)
Wall height uses the tallest wall you enter, since a room is typically papered to one consistent strip length even if a soffit or vaulted section varies slightly. Total wall width is the sum of every wall's width, minus any full-height openings you subtract.
Worked example
A 12 ft × 10 ft bedroom (four walls at 8 ft tall), one 3 ft door, European rolls, with a 20.5 in pattern repeat:
- Total wall width: 12 + 12 + 10 + 10 − 3 (door) = 41 ft.
- Usable strip length: 33 − (20.5 ÷ 12) ≈ 31.3 ft.
- Strips per roll: floor(31.3 ÷ 8) = 3 strips.
- Strips needed: ceil(41 ÷ (21 ÷ 12)) = 24 strips.
- Rolls: ceil(24 ÷ 3) = 8 rolls.
Drop the pattern repeat to 0 for the same room and strips-per-roll rises to 4, cutting the order to 6 rolls — the repeat alone accounts for the extra 2 rolls in this example.
Roll sizes
| Type | Width | Length |
|---|---|---|
| European roll | 21 in | 33 ft |
| US roll (varies) | custom | custom |
US wallpaper is sold in a wider range of roll sizes than the standard European roll, so switch to Custom and enter the width and length printed on your product's label.
Measuring your room
- Walls — measure each wall's width and its own height if it varies; the tallest is used for strip length.
- Doors — subtract full-height openings like doors from total width.
- Windows — usually left in, since paper is still needed above and below most windows.
- Accent walls — enter just the one wall; consider a buffer roll per the FAQ below.
How much does wallpaper cost?
Rather than quoting a national average that's stale the day it's published, this calculator prices the job from what you actually enter. Give a price per roll and a price per paste unit — paste quantity assumes one unit covers about four rolls, a common ratio for wallpaper paste — and both are itemized and totaled. The estimate doesn't include a paste brush, smoothing tools, or wall prep.
Frequently asked questions
How does pattern repeat affect how many rolls I need?
Every strip has to start at a matching point in the pattern, so a length equal to the repeat is lost off the usable roll length for each strip. A large repeat can drop strips-per-roll enough to push the total roll count up noticeably, even though the wall size hasn't changed.
Do I need extra for an accent wall vs a full room?
The formula works the same for either, but rounding losses matter more on a small job, since a single wall often only uses a fraction of a roll's last strip. It's worth ordering one extra roll as a buffer on an accent wall in case of a dye-lot mismatch later.
Pre-pasted vs paste-the-wall — does it change quantity?
No — roll quantity is the same either way. Paste-the-wall products need adhesive applied to the wall rather than activated on the paper, and that adhesive is usually sold by coverage area, so treat the paste estimate here as approximate for that type.
Can leftover rolls be returned?
It depends on the retailer — many accept unopened rolls in original packaging within a return window. It's often worth keeping one leftover roll for repairs instead, since wallpaper is produced in dye lots that can vary between orders.