Calculator

Wallpaper calculator

Enter the room, its doors and windows, the roll and the pattern repeat. The calculator counts the drops that go round the room, how many drops each roll gives once the repeat is allowed for, the short pieces still needed over the doors and windows, and so how many rolls to buy, with the drops drawn on the walls.

Plan the room first Paint calculator

Wallpaper calculator

Feet and inchesMetres

Room length

Room width

Wall height

Doors

Each 3 ft wide (6 ft 8 in high).

Windows

Each 3 ft wide (5 ft high), its top level with a door's.

Roll

US double roll (20.5 in × 33 ft)European (20.9 in × 33 ft)

Pattern repeat

On the roll's label; 0 for a random match.

Match

StraightDrop (half drop)

Trim allowance per drop

Extra length on each drop, trimmed off at the ceiling and the floor.

Rolls to buy

9 rolls

26 drops of 8.7 ft, 3 from each roll

10 short pieces above the doors and above and below the windows, all from the offcuts

43 ft of wall to cover in full drops, 344 ft²

Drops: 26
Per roll: 3
Short pieces: 10
Cut length: 8′ 9″

Walls, unfolded, in drops

1′ 9″ roll

How each roll is used

33 ft

3 rolls, each33 ft
1 roll33 ft
4 rolls, each33 ft
1 roll33 ft

On the wall
Pattern and trim
Short pieces
Offcut

Open as a floor plan

The formula

Wall to cover: the room's perimeter, 2 × (length + width), less the width of each door and window.
Drops: that length ÷ the roll width, rounded up. A drop is one full-height strip.
Cut length: the wall height plus the trim allowance. For a straight match, round it up to a whole number of pattern repeats, so every drop starts at the same point of the pattern; for a drop match, add one full repeat instead, because alternate drops start half a repeat apart.
Drops per roll: the roll length ÷ the cut length, rounded down. What is left at the end of each roll is offcut.
Short pieces: an opening's width comes off, but the wall above a door, and above and below a window, still needs paper: one piece for each roll width the opening spans, each cut like a drop (its height plus trim, rounded to the repeat).
Rolls: drops ÷ drops per roll, rounded up. The short pieces are cut from the offcuts at the end of the rolls where they fit; any that do not take extra rolls.

Assumptions and sourcesRolls: a US double roll (a bolt) is 20.5 in × 33 ft, 56 ft² (Brewster Wallcovering); some US papers come 27 in × 27 ft, so check your label. A European roll is 0.53 × 10.05 m (A.S. Création, Boråstapeter). Trim: York Wallcoverings' hanging instructions cut each strip "4 inches longer than the height", 2 in at the top and bottom; A.S. Création adds about 5 cm. Doors and windows: a door 3 ft × 6 ft 8 in and a window 3 × 5 ft; in metric 0.9 × 2.1 m and 1.2 × 1.2 m. We take a window's top level with a door's; measure yours if it is not. Their width comes off the perimeter, and the short pieces above a door and above and below a window are counted back in, from the rolls' offcuts or from extra rolls (the drawing shows them paler). Drop match: no maker we found publishes how to estimate it, so the extra full repeat is our method, and it errs on the side of more paper. Brewster's rule of thumb, one bolt for about 6 ft of wall up to 9 ft high and one bolt less for every four doors or windows, makes a useful check.

Worked example

A 14 × 12 ft room with 8 ft walls, one door and two windows, in US double rolls with a 21 in straight-match repeat. The perimeter is 52 ft, less 9 ft of openings: 43 ft, or 516 in, of wall. 516 ÷ 20.5 = 25.2, so 26 drops. Each drop is 96 + 4 = 100 in, which rounds up to five repeats, 105 in. A 33 ft roll is 396 in, so it gives 3 drops with 81 in left over. 26 ÷ 3 = 8.7, so 9 rolls for the drops. The door and the two windows each span two roll widths, so 10 short pieces still go over them: 16 in above the door and above each window, one 21 in repeat with the trim, and 20 in below each window, two repeats (42 in). They all come out of the offcuts, 81 in on each full roll and 186 in on the last, so 9 rolls. Brewster's check: 52 ft ÷ 6 = 8.7 bolts, less three openings, about 8 to 9.

US double rolls (20.5 in × 33 ft) for common rooms, a 21 in straight-match repeat unless noted, 4 in trim, worked with the calculator
Room	Doors, windows	Drops	8 ft walls	9 ft walls	9 ft walls, 21 in drop match
10 × 10 ft	1, 1	20	7 rolls	8 rolls	10 rolls
10 × 12 ft	1, 1	23	8 rolls	9 rolls	12 rolls
12 × 12 ft	1, 2	23	8 rolls	9 rolls	12 rolls
12 × 14 ft	1, 2	26	9 rolls	10 rolls	13 rolls
14 × 16 ft	1, 2	30	10 rolls	12 rolls	15 rolls
16 × 20 ft	2, 3	34	12 rolls	14 rolls	17 rolls

On 9 ft walls the 21 in straight match cuts 126 in a drop, six repeats: a roll still gives three drops, but its 18 in offcut is too short for the pieces over the doors and windows, so they take one or two more rolls. With no repeat, 9 ft walls take the same rolls as 8 ft. A 21 in drop match on 9 ft walls needs 133 in a drop, and the roll gives only two. The repeat matters more with European rolls: a 4 × 3 m room with 2.4 m walls, a door and a window, needs 23 drops of 0.53 m; with no repeat each 10.05 m roll gives four drops, so 6 rolls for the drops and a 7th for the 8 short pieces over the openings, while a 53 cm straight-match repeat makes each drop 2.65 m, three to a roll, and 8 rolls, the pieces from their offcuts.

Before you order

One batch. Rolls from different print runs can differ in shade; buy them all at once and check that the batch number on each label is the same.
A spare roll is worth keeping for repairs, since the same batch is hard to find later.
Match type is printed on the label with the repeat: straight (the pattern lines up across the seam), drop or half drop (it steps down by half a repeat), or random (no repeat).

Every room at once

FloorGen's Schedules and budget panel (in the account menu) gives each room's wall area net of its doors and windows. See materials estimate from a floor plan for a worked house.

Questions

How many rolls of wallpaper do I need for a 12 × 12 room?

With 8 ft walls, a door and two windows, 23 drops of a 20.5 in US double roll; each 33 ft roll gives three drops, so 8 rolls, with the short pieces over the door and windows cut from the offcuts. A large drop-match repeat on taller walls can push it to 12.

What is a double roll of wallpaper?

In the US, wallpaper is priced by the single roll but sold in double rolls (bolts). Brewster's double roll is 20.5 in wide and 33 ft long, about 56 ft². A European roll is 53 cm by 10.05 m, about 5.3 m².

How does the pattern repeat change the amount?

Every drop must start at the same point of the pattern (or alternate between two points for a drop match), so each drop is cut longer than the wall by up to one repeat. A longer cut can mean one fewer drop from each roll, and that can add several rolls.

Do I subtract doors and windows?

This calculator takes their width off the perimeter, which saves a full drop for most doors, then counts back the short pieces above doors and above and below windows. They come from the offcut at the end of each roll when it is long enough, and from an extra roll when not: 9 ft walls with a 21 in repeat leave only 18 in at the end of each roll.

How much extra should I allow for trimming?

York's instructions cut each strip 4 in longer than the wall, 2 in at the top and 2 in at the bottom; A.S. Création suggests about 5 cm. The calculator adds that before rounding to the repeat.