Wallpaper Calculator

Written byOleh Soloninupdated 25 September 2026

Room length, m

Room width, m

Ceiling height, m

Windows

Window width, m

Window height, m

Doors

Door width, m

Door height, m

Roll width, m

Roll length, m

Pattern match

The match type and repeat are printed on the roll label.

Advanced options

Trimming allowance, cm per strip

Added to every strip for trimming at the ceiling and skirting.

Other openings, m²

Reduces the wall area only, not the number of strips.

Result

Rolls5
With a spare6
Full-height strips14
Short pieces3 above doors and below windows, 3 from offcuts
Strips from the first roll3
Length of one strip, m2.7
Wall area less openings, m²42.2
Offcut, m9.15

Counts strips and cuts each roll the way a decorator does

Work out how many rolls of wallpaper a room needs, strip by strip rather than by square metre, with windows and doors, short pieces cut from offcuts, and straight or offset (drop) pattern matching.

Estimating wallpaper by area is a reliable way to come up short. Paper goes up in strips, and the end of a roll too short for a full strip is waste. So the calculator works out how many strips the room needs and how many each roll yields.

Above a door and below a window you do not need a full-height strip, only a short piece, and those are usually cut from offcuts. The calculator does the same: it cuts the full strips first, then looks for leftovers long enough for the short pieces, and only adds a roll if none are.

How to use

Enter the room's length, width and height, and the number and size of windows and doors.
Enter the roll size from the label and the pattern match: free, straight or offset. For straight and offset matches add the repeat, and for offset the drop as well.
Read how many rolls you need, how many strips each roll gives and how many short pieces come out of the offcuts.

How many rolls a room needs

The count depends on the perimeter, the height and the roll width. A 10.05 m roll gives four strips at 2.5 m high but only three at 2.7 m, so 20 centimetres of ceiling height can add a roll or two.

10.05 m rolls, free match, one 1.5 × 1.4 m window and one 0.8 × 2 m door, no spare roll. Worked out with this calculator.
Room	0.53 m roll, 2.5 m ceiling	1.06 m roll, 2.5 m ceiling	0.53 m roll, 2.7 m ceiling	1.06 m roll, 2.7 m ceiling
3 × 3 m	6	3	7	4
3 × 4 m	7	4	8	4
3.5 × 5 m	8	4	10	5
4 × 5 m	8	5	10	5
4 × 6 m	9	5	12	6

Working it out by hand

1. Full-height strips: (perimeter − width of doors and windows) ÷ roll width, rounded up. For a 5 × 3.5 m room with a 1.5 m window and a 0.8 m door: (17 − 2.3) ÷ 1.06 = 13.9, so 14 strips.

2. Strips per roll: roll length ÷ strip length, rounded down. 10.05 ÷ 2.7 = 3.7, so 3 strips.

3. Rolls: 14 ÷ 3 = 4.7, so 5 rolls. The pieces above the door (0.7 m) and below the window (1.3 m) come out of the 1.95 m left on each roll after three strips.

Pattern repeat and matching

The repeat is the distance at which the pattern starts over. With a straight match every strip starts at the same point in the pattern, so a piece is cut away between strips to reach the next repeat. With an offset or drop match every other strip starts part of a repeat lower.

How many rolls that costs depends on the height. With a 64 cm straight match a roll gives three strips instead of four at a 2.5 m ceiling, but at 2.7 m it gives the same three as plain paper.

Strips from a 10.05 m roll. Worked out with this calculator.
Match	2.3 m ceiling	2.5 m ceiling	2.7 m ceiling
Free	4 strips	4 strips	3 strips
Straight, 64 cm repeat	4 strips	3 strips	3 strips
Offset, 64 cm repeat, 32 cm drop	3 strips	3 strips	3 strips

What this calculator shows

The number of rolls, and the figure with one spare
Full-height strips and how many each roll yields
Short pieces above doors and below windows, and how many come out of offcuts
How many metres end up as offcuts

What to keep in mind

Strips hang vertically and butt-joined; horizontal hanging needs a different calculation.
Above and below a window is treated as one piece as long as the ceiling height less the window height; with a high sill it is two pieces of the same total length.
Each new roll is started at whichever point of the pattern the next strip needs.
Roll size and repeat vary by maker, so take them from your label rather than the defaults.

Where the numbers come from

Checked against GOST 6810-2002 (wallpaper specifications, with amendment 1), clause 4.6 for roll length and width and annex V for pattern match types · verified September 2026.

FAQs

How many rolls of wallpaper do I need?

Count strips: divide the perimeter, less the width of windows and doors, by the roll width. Then divide the roll length by the strip length to get strips per roll. A 5 × 3.5 m room with a 2.7 m ceiling and 1.06 × 10.05 m rolls needs 14 strips at 3 a roll, which is 5 rolls.

What does a repeat like 64/32 mean?

It is an offset match: the pattern repeats every 64 cm and the next strip is dropped by 32 cm. A straight match gives only the repeat.

Why not work out wallpaper by area?

Because the end of a roll shorter than a strip cannot go on the wall as a full drop. A 1.06 × 10.05 m roll covers 10.65 m² on paper, but at a 2.7 m ceiling it gives three strips, or 8.59 m² of wall.

Do I deduct windows and doors?

Deduct their width from the full-height strips, but remember the short pieces above and below them. The calculator counts those and fits them into offcuts, which can save a roll compared with ignoring the openings altogether.

Does a bigger pattern repeat always need more rolls?

Not always. It depends on how the ceiling height lines up with the repeat: a 64 cm straight match costs a strip per roll at 2.5 m but none at 2.7 m. Enter your own height and repeat to see.

Should I buy a spare roll?

A spare lets you replace a damaged strip with paper from the same batch; the batch number is on the label. The With a spare line shows the count including one.

Worked example

A 5 × 3.5 m room with plain paper

Input: Room 5 × 3.5 m, 2.7 m ceiling, 1.5 × 1.4 m window, 0.8 × 2 m door, 1.06 × 10.05 m roll

Output: 14 full-height strips, 3 per roll, 5 rolls

Note: The three short pieces above the door and below the window come out of offcuts. Without deducting the openings it would take 17 strips and 6 rolls.

Useful links

All tools in Building & Repair

Wallpaper Calculator

Result

Related tools

Wall Area Calculator

Paint Calculator

Drywall Calculator

Useful links