Wallpaper Calculator
Find how many rolls of wallpaper to buy for a room or a single wall. Enter the walls, the roll size, and the pattern repeat and match on the label to see the strips you need, how many strips each roll gives, and the rolls to buy.
Use the height you'll paper, from the top of the baseboard to the ceiling. Add more walls, or subtract doors and windows.
- Choose US or Metric. You can still change the unit of any single field.
- The first section is set to Room walls. Enter the room's Length and Width and the Height you'll paper, measured from the top of the baseboard to the ceiling. For a single wall, choose Rectangle and enter the wall's Length and Height.
- Use Add section for more walls. To leave out doors and windows, add a section for each one, measure it, and set it to Subtract. Use Quantity for several of the same size.
- Choose the Roll size. For another size, choose Custom size and enter the width and full length on the label.
- Choose the Pattern match and enter the Pattern repeat printed on the label. Leave the repeat blank for plain or textured wallpaper.
- Check the Trim allowance, which starts at 4 in or 10 cm, and the Waste allowance, which starts at 10%.
- Optionally, enter a price per roll, or per single roll for US rolls, to estimate the cost.
Dimension fields accept whole numbers, decimals, fractions, and mixed
numbers, such as 12, 20.5, 3/4, or
7 11/16.
How many rolls of wallpaper you need
Wallpaper is hung in full-height strips cut from the roll, so the calculator counts strips rather than dividing the area by the area of a roll:
Total area = net wall area × (1 + waste % ÷ 100)
Strips = total area ÷ (roll width × wall height), rounded up
Strips per roll = roll length ÷ strip length, rounded down
Rolls = strips ÷ strips per roll, rounded up
The strip length is the wall height plus the trim allowance, made longer for the pattern match. Only whole strips count, so the leftover end of each roll is not used for another full-height strip. The wallpaper wholesaler James Dunlop Textiles describes the same method: divide the strip length into the length of the roll, and count only full strips.
The number of strips per roll changes in steps with the wall height. With a 33 ft roll and a 4 in trim allowance, you get 4 strips when the height you paper is 7 ft 11 in or less, but only 3 at 8 ft. In a 12 × 12 ft room, that's 11 rolls instead of 8 for almost the same area. That's why the calculator doesn't use a fixed area per roll, such as the 25 usable square feet per single roll that Sherwin-Williams suggests.
The wall height is the tallest section you add, and every strip is cut to that height. Harlequin and Boråstapeter both say to use the highest measurement when the ceiling height varies. For walls with a very different height, such as a stairwell, calculate them separately. For a gable wall or a wall under a sloped ceiling, enter a rectangle using its tallest and widest points. The area of each shape is calculated as follows:
| Shape | Area |
|---|---|
| Room walls | 2 × (length + width) × height |
| Rectangle | length × height |
The calculator subtracts the doors and windows you enter. Harlequin and James Dunlop Textiles recommend not subtracting them. James Dunlop Textiles notes that cutting around them uses about as much paper as a full strip. Leave them out for a more generous count.
Wallpaper roll sizes
| Roll | Area | Examples |
|---|---|---|
| 20.5 in × 33 ft (US double roll) | about 56 ft² | York Wallcoverings, Brewster |
| 27 in × 27 ft (US double roll) | about 61 ft² | Thibaut, as listed by Designer Wallcoverings |
| 53 cm × 10.05 m (UK and Europe) | about 5.3 m² | Boråstapeter, Wickes |
In the US, wallpaper is sold in double rolls but is often priced per single roll, which is half a double roll. Sherwin-Williams notes that wallpaper is priced in single rolls but sold only in double or triple rolls. A double roll is still one physical roll. The calculator counts double rolls and shows the number of single rolls next to them, so you can compare with a single roll price. UK and European rolls are sold one at a time and are about the same size as a US double roll.
For other sizes, such as the 52 cm and 72 cm wide rolls that James Dunlop Textiles mentions, or peel-and-stick rolls like the 20.5 in × 18 ft rolls that WallPops sells as single rolls, choose Custom size and enter the width and length on the label. For a US double roll, enter its full length, such as 33 ft. If a Custom size roll is a double roll priced per single roll, enter twice the single roll price.
Pattern repeat and pattern match
The pattern repeat is the vertical distance before the pattern repeats. The pattern match is how the pattern lines up from one strip to the next. Both are printed on the label. They make each strip longer:
| Pattern match | Strip length |
|---|---|
| Free match | wall height + trim allowance |
| Straight match | wall height + trim allowance, rounded up to a whole number of repeats |
| Half drop match | wall height + trim allowance + one repeat |
With a straight match, every strip starts at the same point of the pattern, so each strip uses a whole number of repeats. The German retailer meinewand calculates it the same way. With a half drop match, every other strip starts half a repeat lower. Adding one repeat to each strip is enough however you cut the strips, which is also how the Cole & Son calculator works. Use the half drop match for other drop matches, such as a third drop. Free and random matches don't need the repeat.
Trim allowance and extra rolls
The trim allowance is the extra length on each strip that you trim off at the ceiling and the baseboard. York Wallcoverings recommends about 4 in, 2 in at each end, so the calculator starts at 4 in. Selected Wallpapers uses about 5 cm at each end, so the metric default is 10 cm. James Dunlop Textiles adds 15 cm at each end. With a 2.4 m wall and a 10.05 m roll, a 10 cm allowance gives 4 strips per roll and a 30 cm allowance gives 3, so increase it only if the pattern is large or the walls are uneven.
The waste allowance starts at 10%, as Graham & Brown and James Dunlop Textiles recommend. It covers miscut strips, the part-width strips at the end of each wall, and uneven walls. James Dunlop Textiles suggests 15% to 20% for a pattern repeat over 26 cm, or about 10 in. Cole & Son, Harlequin, and Farrow & Ball recommend buying one more roll.
Buy all the rolls with the same batch or lot number, printed on the label, so the colors match.
Examples
A bedroom
The walls of a room 12 ft × 10 ft with 8 ft walls are 352 ft². Subtract a door 3 ft × 7 ft and two windows 3 ft × 4 ft to get 307 ft², or 337.7 ft² with 10% added. A 20.5 in wide strip 8 ft tall covers about 13.67 ft², so you need 25 strips. Each strip is 8 ft 4 in with the trim allowance, and a 33 ft roll gives 3 of them. That's 25 ÷ 3 = 8.33, so buy 9 double rolls, or 18 single rolls.
A pattern with a 24 in repeat
In the same room with 7 ft 8 in walls, plain wallpaper needs 25 strips 8 ft long, 4 per roll, so 7 rolls. With a 24 in straight match, 8 ft is 4 repeats, so it still takes 7 rolls. With a 24 in half drop match, each strip is 10 ft, only 3 fit on a roll, and you need 9 rolls.
Metric dimensions
The walls of a room 4 m × 3.5 m with 2.4 m walls are 36 m², or 39.6 m² with 10% added. A 53 cm wide strip 2.4 m tall covers 1.272 m², so you need 32 strips. Each strip is 2.5 m with the trim allowance, and a 10.05 m roll gives 4 of them, so buy 8 rolls. With a 64 cm half drop match, each strip is 3.14 m, a roll gives 3, and you need 11 rolls.
FAQ
About 11 double rolls of 20.5 in × 33 ft wallpaper when the height you paper is 8 ft, or 8 double rolls when it's 7 ft 11 in. With 10% extra and no doors or windows subtracted, the walls take 31 strips either way. Strips 8 ft 4 in long fit 3 to a roll, and strips 8 ft 3 in long fit 4. Measure from the top of the baseboard, not from the floor.
A single roll is half a double roll. In the US, wallpaper is sold in double rolls, one physical roll twice as long, but is often priced per single roll. Check whether a price is per single roll, or the cost comes out half or double.
Subtracting them gives the area you'll actually cover. Some makers recommend counting the walls as full walls, because cutting around openings uses about as much paper as a straight strip. Leave the doors and windows out for a more generous count.
About 10% extra, or 15% to 20% for a pattern repeat over 26 cm (about 10 in). Many makers also recommend one extra roll from the same batch.
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