Paint & Flooring
Wallpaper Calculator
Find out how many rolls of wallpaper you need. Enter your walls, the roll size and the pattern repeat, and this wallpaper calculator counts the strips to hang, how many strips each roll gives, and the rolls to buy, with the cost.
Result
Enter your measurements and press Calculate. What to buy, the working and the cost will appear here.
How to use the wallpaper calculator
- Enter each wall’s width and height. Use How many for matching walls.
- Doors and windows are optional; only large openings save whole strips.
- Pick the roll size or enter the width and length from the label.
- Enter the pattern repeat (0 for plain or random-match paper) and press Calculate.
How many rolls of wallpaper do I need?
Wallpaper is hung in full-height strips, so it is counted in strips, not square feet:
strips = total wall width ÷ roll width, rounded up
strips per roll = roll length ÷ (wall height rounded up to the pattern repeat), rounded down
rolls = strips ÷ strips per roll, rounded up, plus a spare
Dividing wall area by roll area underestimates, because the end of every roll is too short for another full strip.
Worked example: a 14 × 12 ft bedroom
All four walls of a 14 × 12 ft bedroom, 8 ft high, with a door and window totaling 35 ft², in a paper with a 21 in repeat on 20.5 in × 33 ft rolls at $45:
- Strips across the walls: 52 ft ÷ 20.5 in roll width = 30.44 → 31 − 2 for doors and windows = 29
- Strip length: 8 ft wall rounded up to 5 × 21 in repeat = 8.75 ft
- Strips per roll: 33 ft ÷ 8.75 ft, rounded down = 3
- Rolls: 29 strips ÷ 3 per roll = 9.67, plus allowance → 11
Rolls to buy: 11; Strips needed: 29; Wall area: 381 ft²; Estimated cost: $495.00. Open this example in the calculator.
Pattern repeat and match
- Random match (plain, textured, stripes): no waste from matching; repeat is 0.
- Straight match: the pattern lines up horizontally across strips; each strip is rounded up to whole repeats.
- Drop (half-drop) match: alternate strips are offset by half a repeat, which wastes a little more; a 10–15% allowance covers it.
Large repeats cut the number of strips you get from each roll, so a big pattern can need noticeably more rolls than a plain paper for the same wall.
Wallpaper roll sizes
| Roll | Size | Area |
|---|---|---|
| US double roll | 20.5 in × 33 ft | about 56 ft² |
| US wide roll | 27 in × 27 ft | about 61 ft² |
| European standard roll | 0.53 × 10.05 m | about 5.3 m² (57 ft²) |
Many US papers are priced per single roll but sold only in double rolls; check what one “roll” means before comparing prices.
Assumptions and limitations
- Every strip is cut to the tallest wall; rooms with very different wall heights may use a little less.
- Only openings large enough to save whole strips reduce the count.
- At least one spare roll is added when the allowance is above zero.
Wallpaper questions
How many rolls of wallpaper for a 12 × 12 room?
With 8 ft walls and plain paper on 20.5 in × 33 ft double rolls: 48 ft of wall needs 29 strips, each roll gives 4 strips, so 8 rolls, or 9 with a spare.
How do I measure for wallpaper?
Measure the width of each wall and the height from skirting to ceiling at the tallest point. Note the pattern repeat on the label.
Should I buy extra wallpaper?
Yes, at least one roll from the same batch. Rolls from a later batch can differ in shade.
Formulas, unit conversions and default values are explained on our methodology page. Results are estimates; check manufacturer data and local codes before you buy or build.