Wallpaper Calculator With Pattern Repeat: Rolls Needed

Use this wallpaper calculator to find how many rolls you need for a room or a single accent wall. It uses the strip method, the way paperhangers measure, so it counts the waste from pattern repeat and trimming. Enter the wall size, your roll size and the pattern repeat.

Room length

Room width

Wall width

Wall height

Full-height openings to skip

ft wide

Roll size

Roll width

Roll length

Pattern repeat

Pattern match

Trim allowance, spare rolls and cost

Trim allowance per strip

Spare rolls

rolls

Price per roll

Installation per roll

–rolls of wallpaper

–strips to hang

–cut length of each strip

–strips from each roll

–linear yards of paper

–sq ft of wall

–estimated cost

Order every roll from the same batch (dye lot) so the color matches. Roll sizes vary by maker, so check the label.

How the wallpaper calculator works

Wall width = 2 × (room length + room width) for a room, minus any full-height openings you skip
Strips = wall width in inches ÷ roll width, rounded up
Cut length = wall height + trim allowance (4 in by default), rounded up to a whole pattern repeat
Half-drop match adds half a repeat to each strip. Random match needs no extra.
Strips per roll = roll length ÷ cut length, rounded down
Rolls = strips ÷ strips per roll, rounded up, plus spare rolls (1 by default)

Doors and normal windows are not taken off, because the pieces above and below them still use full-length strips. Only skip wide openings that run from floor to ceiling.

Worked example

A 14 × 12 ft room with 8 ft walls, using 20.5 in × 33 ft rolls with a 21 in straight-match repeat:

Wall width: 2 × (14 + 12) = 52 ft, or 624 in
Strips: 624 ÷ 20.5 = 30.4, rounded up to 31 strips
Cut length: 96 + 4 = 100 in, rounded up to 5 repeats of 21 in = 105 in (8 ft 9 in)
Strips per roll: 396 ÷ 105 = 3.8, rounded down to 3
Rolls: 31 ÷ 3 = 10.3, rounded up to 11, plus 1 spare = 12 rolls
Paper used: 31 × 105 in = 90.4 linear yards

With a half-drop match, each strip grows to 115½ in. Each roll still gives 3 strips, so the count stays at 12 rolls.

Common roll sizes

Roll	Size	Area	8 ft strips per roll, no repeat
US double roll	20.5 in × 33 ft	About 56 sq ft	3
US double roll, wide	27 in × 27 ft	About 61 sq ft	3
European roll	20.9 in × 33 ft (0.53 × 10.05 m)	About 57 sq ft	3
Peel and stick	20.5 in × 18 ft	About 31 sq ft	2

Usable area is always less than the label area, because of trimming and pattern match. That is why the strip method gives a better count than dividing square feet.

Rolls for common rooms

For 8 ft walls, 20.5 in × 33 ft rolls and a 21 in straight repeat, including 1 spare roll:

Room	Strips	Rolls to buy
10 × 10 ft	24	9
10 × 12 ft	26	10
12 × 12 ft	29	11
14 × 12 ft	31	12
16 × 14 ft	36	13
20 × 16 ft	43	16

Tips for wallpapering

Check that every roll has the same batch or dye lot number. Rolls from different batches can differ slightly in color.
Prime the walls with a wallpaper primer first. It helps the paper stick and makes it easier to remove later.
Start next to a door or in a corner where a pattern break won’t show.
Large repeats waste more paper. A 25 in repeat on a 9 ft wall can leave a long offcut from every strip.
Keep the spare roll for repairs. The same batch can be hard to find later.
For a feature wall in paint instead, the paint calculator works out gallons. The square footage calculator gives the wall area.

Frequently asked questions

How do I calculate how much wallpaper I need?

Count the strips, not the square feet. Divide the wall width by the roll width to get strips. Work out how many full-height strips you can cut from one roll, including the pattern repeat. Then divide the strips by strips per roll and round up.

What is a pattern repeat?

It is the distance before the pattern starts again, printed on the label. With a straight match, the pattern lines up across strips at the same height. With a half-drop match, every other strip is shifted down by half a repeat, which uses more paper.

How many square feet are in a roll of wallpaper?

A common US double roll of 20.5 in × 33 ft has about 56 sq ft. After trimming and matching, you can usually use only about 45 to 50 sq ft of it, depending on the repeat and wall height.

Should I subtract doors and windows?

Usually not for normal doors and windows, because the pieces above and below them still come from full strips, and the extra covers mistakes. Do subtract wide openings that run from floor to ceiling, like a large archway.

How much does wallpaper installation cost?

Installers often charge per roll or per square foot, and prices vary a lot by region and paper type. Enter the price per roll and the installer’s price per roll in the calculator to get a total.

Results are estimates for planning. Roll sizes and repeats vary by maker, so check the label before you order. See How We Calculate for the formulas we use.