Wallpaper Calculator: How Much Wallpaper Do I Need?

How to measure for wallpaper

1. Measure the width of every wall you are papering. Add them together to get the total wall width. For one accent wall, that is just its width. If you are painting the other walls, the paint calculator works from the room's length, width, and height.
2. Measure the wall height. Go from the top of the baseboard to the ceiling or crown molding, which is where the paper will actually go. Measure in a few spots and use the tallest. If you are replacing the baseboard too, the baseboard calculator counts the pieces.
3. Count the doors and windows. The calculator removes about 18 sq ft for each opening. Leave small windows out of the count if you want a safer number.
4. Find the roll coverage. The label or product page lists the roll width and length. Multiply them to get square feet, and note whether the price is per single or per double roll.
5. Find the pattern repeat and match type. The repeat is the vertical distance before the pattern starts over. Write it down; you need it for the strip check.

In the calculator, enter the walls in feet, even for a Euro roll (1 m is 3.28 ft). For a strip count, also set the Roll size (US double, wide, Euro, peel-and-stick, or a custom width and length), the Pattern repeat in inches (0 if there is none), and the Match type (Random, Straight, or Half-drop). The result then shows the strips you need, the strips per roll, and the rolls to buy, with the area estimate underneath. Left at their defaults, these fields give the area estimate alone.

Check it with a strip count

The area method assumes every inch of the roll ends up on the wall. In practice, you cut the roll into full-height strips, and each strip has to start at the same point in the pattern. Family Handyman recommends working in strips rather than square feet, which builds the pattern repeat into the count:

1. Strips needed = total wall width in inches / roll width in inches, rounded up
2. Length of each strip = wall height in inches + pattern repeat
3. Strips per roll = roll length in inches / strip length, rounded down
4. Rolls = strips needed / strips per roll, rounded up

Take the same 14 ft (168 in) wall with a 20.5 in x 33 ft (396 in) double roll and a 24 in repeat. You need 168 / 20.5 = 8.2, so 9 strips. Each strip is 96 + 24 = 120 in, so one roll gives 3 strips. Nine strips divided by 3 is 3 double rolls. The door replaces one or two full-length strips, but 7 or 8 strips still take 3 rolls, and you need short pieces above the door as well. So 3 double rolls is the safe order.

That is one double roll more than the area estimate. For large repeats, raise "Extra for pattern match" until the calculator agrees with your strip count. On this wall, with coverage entered as 28 sq ft single rolls, it takes about 50 percent to reach 6 single rolls (3 double rolls).

Strips per double roll by wall height and repeat

Use this chart for the strip check. Each cell shows the number of full strips you get from one double roll: first for a 20.5 in x 33 ft roll, then for a 27 in x 27 ft roll.

The no-repeat column assumes minimal trim: 4 strips from a 33 ft roll on an 8 ft wall leave about 1.5 in at each end. If you trim 2 in at the top and bottom of each strip, use the 6 in repeat column.

Notice how quickly the count drops. A roll that yields 4 strips on an 8 ft wall with a random-match paper yields only 3 once there is any repeat, and a wide 27 in roll with a big repeat yields just 2.

How many rolls of wallpaper do I need for my room size?

A 12 x 12 room with 8 ft walls takes 29 strips of 20.5 in wallpaper: 8 double rolls of a random-match paper or 10 double rolls of a patterned paper. The table counts full-height strips for common room sizes.

Assumptions: 8 ft of wall to paper (96 in), US double rolls of 20.5 in x 33 ft, all four walls, and no doors or windows subtracted. Random match = 4 strips per roll (396 / 96 = 4.1). Patterned = 3 strips per roll, because each strip is the wall height plus one repeat, and 96 + 36 = 132 in still fits three times in 396 in. The patterned column also covers random-match paper if you want 2 in of trim at the top and bottom of each strip. Add one spare roll from the same run.

For 9 ft walls, use the patterned column for random-match paper and for repeats up to 24 in. Repeats over 24 in on 9 ft walls leave only 2 strips per roll, so run the strip check. With a lot of doors and windows, Brewster Wallcovering's rule of thumb is to take off one double roll for every four ordinary-size doors or windows.

Sources for the inputs: York Wallcoverings (roll size), Canvas & Ivy (2 in trim at each end), and Brewster Wallcovering (openings rule).

Wallpaper roll sizes

York Wallcoverings produces rolls in both of those widths and notes that each holds about the same square footage. The single roll survives mostly as a pricing unit, so read the listing carefully: a price "per single roll" usually means you must buy in pairs.

How wide is a roll of wallpaper?

Residential wallpaper made for the US usually comes in two widths, 20.5 in and 27 in, with grasscloth the exception, according to Wallpaper Boulevard. A double roll is 33 ft long in the 20.5 in width and 27 ft long in the 27 in width, the two sizes York Wallcoverings produces, and a single roll is half as long: 16.5 ft or 13.5 ft.

European rolls are metric. The standard Euro roll is 53 cm wide and 10.05 m long (about 20.9 in x 33 ft), the size Boråstapeter and A.S. Création list, which is 5.3 square meters or about 57 sq ft. Arthouse, a UK wallpaper maker, uses 10 m x 53 cm in its roll calculator. Decorators Best describes the Euro roll that many English companies use as a single roll 20.5 in wide and 11 yards long, about 56 sq ft, so one Euro roll holds about as much paper as a US double roll. In the calculator, enter about 56 sq ft per roll for a Euro roll or a US double roll, and 28 for a US single roll. The square footage calculator also shows any area in square meters if you want to compare it with a metric label.

Metric (Euro) rolls: strips per roll by wall height

A 10.05 m Euro roll gives 4 full-height strips on walls up to about 2.45 m high and 3 strips up to 3.3 m, with 5 cm of trim and no repeat. A pattern repeat cuts that down sooner.

Strip length = wall height + 5 cm (the trim A.S. Création suggests) for a random match, or wall height + one repeat for a matched pattern. Strips per roll = 10.05 m / strip length, rounded down. The repeat values are examples only; use the one printed on your roll label.

Match types and how much they waste

• Random or free match: strips go up without lining up the pattern at the seams. Grasscloth, stripes, and many textures work this way. Least waste.
• Straight match: every strip lines up the same way at the ceiling line. Waste depends on the repeat length.
• Half-drop match: every other strip lines up the same at the top, so the pattern steps diagonally across the wall. Tempaper notes that straight and drop matches waste more than random matches, so round up your order.

How much extra a half-drop match needs

I Love Wallpaper plans each half-drop strip as the wall height plus 1.5 times the repeat, against the height plus one repeat for a straight match. On 8 ft walls, a 20.5 in x 33 ft double roll still gives 3 strips for half-drop repeats up to 24 in (96 + 36 = 132 in, and 396 / 132 = 3). On 9 ft walls, any half-drop repeat over 16 in drops the roll to 2 strips, while a straight match keeps 3 strips up to a 24 in repeat. So for repeats of 17 to 24 in, a half drop needs about 50 percent more rolls: a 12 x 12 room with 9 ft walls and a 21 in half-drop needs 15 double rolls (29 strips / 2) instead of 10.

Boråstapeter's calculator also lists third-drop and quarter-drop matches. Plan them like a half drop and run the strip check.

Tips and common mistakes

• Mixing up single and double rolls. If you enter 56 sq ft per roll, the answer is in double rolls. If you enter 28, it is in single rolls.
• Ignoring the repeat. A big, bold pattern can cost a full extra roll on a single wall. Always run the strip check.
• Buying from two runs. York assigns each press run its own run number. Order everything at once and check that every roll carries the same run number.
• Measuring the wrong height. Measure where the paper goes, from the top of the baseboard to the ceiling or crown, not floor to ceiling.
• Counting on remnants. Leftover pieces rarely fit anywhere except above doors and below windows. Plan full-height strips first.
• Skipping a spare. Family Handyman suggests adding an extra roll for mistakes. A spare from the same run is also your only reliable patch material later.