Wallpaper Calculator: How Many Rolls Do I Need?

Estimate only. Check product labels and local building rules before you buy or build.

Quick answer

Divide the width of the walls by the roll width to get the number of strips, then divide the roll length by the wall height plus trim, rounded up to the pattern repeat, to get strips per roll. Strips ÷ strips per roll, rounded up, is the number of rolls. A 12 × 12 ft room with 8 ft walls, one door and one window takes 27 strips of 20.5 in paper, and a 33 ft double roll gives 3 strips of 8 ft 4 in, so you need 9 double rolls.

How to use the wallpaper calculator

Choose Room to enter the length and width of a rectangular room, or Walls to enter the total width of the walls you will paper, such as a single accent wall.
Enter the wall height from floor to ceiling. If the ceiling is not level, use the highest point.
Enter how many doors and windows there are, or 0 if the walls you are papering have none. Their sizes, the trim allowance and the seam overlap are under Trim, overlap and opening sizes.
Pick the roll you are buying, or Other size to type the width and length from the label. Then choose the pattern match and enter the repeat from the label.
Read the rolls to buy. Strips to hang, strips per roll and paper per strip show how the number was reached.

How do you calculate how many rolls of wallpaper you need?

Count strips, not square feet. Wallpaper goes up in vertical strips, so the number of strips across the walls is the total wall width divided by the roll width, rounded up. Each strip is the wall height plus a trim allowance; York Wallcoverings advises about 4 inches, roughly 2 at the ceiling and 2 at the baseboard.

A pattern adds waste. With a straight match every strip starts at the same point of the design, so each strip is rounded up to whole repeats. With a half-drop match each strip starts half a repeat lower than the one beside it, so when you cut strips one after another the paper per strip is rounded up to end on a half repeat. Divide the roll length by the paper per strip and round down to get whole strips per roll, then divide the strips you need by that number and round up.

Doors and windows count only when they replace a whole strip. Their area is divided by the area of one full-height strip and rounded down, because the short pieces above a door and below a window still have to be cut and matched.

The calculator counts the walls as one continuous run, so it assumes the piece left over at the end of one wall starts the next. If you cannot reuse it, for example in a room of many short walls, add one strip for each wall.

strips = wall width ÷ roll width, rounded upstrips saved = door and window area ÷ (roll width × wall height), rounded downcut length = wall height + trimpaper per strip, straight match = cut length rounded up to whole repeatspaper per strip, half drop = whole repeats + ½ repeat, at least the cut lengthstrips per roll = roll length ÷ paper per strip, rounded downrolls = (strips − strips saved) ÷ strips per roll, rounded up

What size is a roll of wallpaper?

A typical US double roll is 20.5 in wide and 33 ft long and covers about 56.4 sq ft. Wider and peel-and-stick rolls cover a different area, so check the label before you count.

Wallpaper roll sizes sold in the US, with coverage and strips per roll on 8 ft walls
Roll	Width × length	Coverage	Strips at 8 ft
Double roll	20.5 in × 33 ft	56.4 sq ft	3
Wide double roll	27 in × 27 ft	60.8 sq ft	3
Peel-and-stick roll	20.5 in × 20 ft	34.2 sq ft	2
Wide peel-and-stick roll	27 in × 20 ft	45 sq ft	2
Euro roll	0.53 × 10.05 m (20.9 in × 33 ft)	57.3 sq ft	3

Sizes and coverage from York Wallcoverings product pages and the A.S. Création roll guide. Strips per roll assume 4 in of trim and no pattern repeat.

How many rolls of wallpaper for a 12×12 room?

A 12 × 12 ft room with 8 ft walls needs 9 double rolls of plain paper. Every figure below assumes 20.5 in × 33 ft double rolls, 4 in of trim, one 36 × 80 in door, one 36 × 48 in window and no pattern repeat.

Double rolls of wallpaper by room size and wall height
Room	8 ft walls	9 ft walls	10 ft walls
10 × 10 ft	8	8	8
10 × 12 ft	8	8	9
12 × 12 ft	9	9	10
12 × 14 ft	10	10	10
14 × 16 ft	12	12	12
16 × 20 ft	14	14	14

8 ft and 9 ft walls need the same number of rolls because a 33 ft roll gives 3 strips at either height. A pattern repeat can add rolls.

Worked examples

A 12 × 12 ft bedroom with 8 ft walls

The four walls add up to 48 ft, or 576 in. With 20.5 in double rolls that is 576 ÷ 20.5 = 28.1, so 29 strips. The 36 × 80 in door and 36 × 48 in window add up to 32 sq ft, and one full-height strip covers 20.5 × 96 in = 13.7 sq ft, so the openings replace 2 whole strips, leaving 27.

Each strip is 8 ft plus 4 in of trim: 8 ft 4 in, or 100 in. A 33 ft roll is 396 in long, and 396 ÷ 100 = 3.96, so you get 3 strips per roll. 27 ÷ 3 = 9 double rolls, which a US price list shows as 18 single rolls.

A patterned accent wall under a 10 ft ceiling

The wall is 15 ft wide and 10 ft high (choose Walls and enter 0 doors and 0 windows), and the paper is a 20.5 in × 33 ft double roll with a 20.5 in straight-match repeat. The width takes 180 ÷ 20.5 = 8.8, so 9 strips. Each strip needs 120 + 4 = 124 in, which is 6.05 repeats, so it rounds up to 7 repeats: 143.5 in, or 11 ft 11.5 in of paper.

A 396 in roll holds 396 ÷ 143.5 = 2.76, so 2 strips, and 9 strips need 5 double rolls. The same wall in a plain paper gets 3 strips per roll and needs 3 double rolls, so this repeat adds 2 rolls.

Should you subtract doors and windows when ordering wallpaper?

Subtract them only where they replace whole strips. Sherwin-Williams measures the area to cover without windows and doors, while Graham & Brown tells buyers to ignore them and treat the extra as a margin for mistakes. Counting only whole strips sits between the two: on 8 ft walls, a 36 × 80 in door and a 36 × 48 in window save 2 strips, about 27 sq ft of paper, rather than the full 32 sq ft they measure.

Whichever way you count, check that every roll has the same run or batch number, because colors can vary slightly between print runs, and keep one spare roll for repairs.

Questions

How many square feet does a double roll of wallpaper cover?

A US double roll of 20.5 in × 33 ft covers about 56.4 sq ft, according to York Wallcoverings product data. You can hang less than that, because each strip is trimmed and lined up with the pattern: Sherwin-Williams counts 25 usable sq ft per single roll, which makes 50 per double roll. Count strips instead of square feet when the walls are tall or the repeat is large.

What is the difference between a single roll and a double roll of wallpaper?

A double roll holds twice the paper of a single roll. In the US, wallpaper is priced per single roll but sold only in double or triple rolls, according to Sherwin-Williams. A typical double roll is 20.5 in wide and 33 ft long, so an order of 9 double rolls appears on a price list as 18 single rolls. Compare prices per double roll to avoid surprises.

How many strips do you get from a roll of wallpaper?

A 33 ft double roll gives 3 strips for plain paper on walls up to 10 ft 8 in high, with 4 in of trim. Divide the roll length by the wall height plus trim and round down: for a 10 ft wall, 396 in ÷ 124 in = 3.19, so 3 strips. A pattern makes each strip longer, and a 20.5 in repeat on the same 10 ft wall drops it to 2 strips per roll.

What does half-drop match mean on wallpaper?

A half-drop match means the design on each strip starts half a repeat lower than on the strip next to it. With a 21 in repeat, neighboring strips are offset by 10.5 in, so every second strip starts at a different point of the pattern on the roll. Like a straight match, a half drop can lose up to one full repeat per strip, depending on how the wall height lines up with the pattern.

How much extra wallpaper should I buy?

Buy one roll more than the count you need, with the same run or batch number as the rest. Sherwin-Williams suggests an extra roll so you do not run out and have paper for later patching, because a new print run can differ slightly in color. Graham & Brown recommends measuring for an extra 10% to cover waste and mistakes.

Sources

York Wallcoverings, Colette Wallpaper (product page) (checked October 19, 2026)Double roll 20.5 in × 33 ft covering about 56.4 sq ft; 20.5 in repeat, straight match.
York Wallcoverings, Hillswick Tweed Wallpaper (product page) (checked October 19, 2026)27 in × 27 ft double roll covering about 60.8 sq ft.
York Wallcoverings, Painted Herringbone Peel and Stick Wallpaper (product page) (checked October 19, 2026)Peel-and-stick roll 20.5 in × 20 ft covering about 34.2 sq ft.
York Wallcoverings, Monarch Peel and Stick Wallpaper (product page) (checked October 19, 2026)Peel-and-stick roll 27 in × 20 ft covering about 45 sq ft.
York Wallcoverings, Wallpaper Installation Guide (checked October 19, 2026)Allow about 4 in of extra length per strip, roughly 2 in at the ceiling and 2 in at the baseboard.
Sherwin-Williams, How much to buy? (checked October 19, 2026)25 usable sq ft per single roll; priced in single rolls, sold in double or triple rolls; matching run numbers; an extra roll for patching.
Graham & Brown, How to measure for wallpaper (checked October 19, 2026)Ignore doors and windows when measuring and allow an extra 10% for waste.
A.S. Création, Calculate wallpaper requirements (checked October 19, 2026)Standard Euro roll 10.05 m × 0.53 m.

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