Wallpaper calculator
Find how many rolls of wallpaper to buy for a room or a feature wall, with the pattern repeat, doors and windows taken into account.
Wall to wall, along the floor.
Floor to ceiling. If it varies, use the highest point.
Sizes are under Trim, overlap and opening sizes.
Rolls to buy
- Rolls to buy
- 9
- Drops to hang
- 252 fewer for doors and windows
- Drops per roll
- 3
- Paper per drop
- 2.55 m
- Wall area to cover
- 31.8 m²
Trim, overlap and opening sizes
Extra for the ceiling and the skirting together.
Leave at 0 for butt-joined seams.
Estimate only. Check product labels and the building rules in your state or territory before you buy or build.
Quick answer
Divide the total width of the walls by the roll width to get the number of drops, then divide the roll length by the ceiling height plus about 5 cm of trim, rounded down, to get drops per roll. Drops ÷ drops per roll, rounded up, is the number of rolls. A 4 × 3 m room with 2.5 m walls, one door and one window takes 25 drops of 530 mm paper, and a 10.05 m roll gives 3 drops of 2.55 m, so you need 9 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 feature 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.
- Keep the standard 10.05 m × 530 mm roll, or pick Other size and type the width and length from the label. Then choose the pattern match and enter the repeat printed on the label.
- Read the rolls to buy. Drops to hang, drops per roll and paper per drop show how the number was reached.
How do you work out how many rolls of wallpaper you need?
Count drops, not square metres. Porter’s Paints does it in two steps: divide the wall length by the roll width (usually 530 mm) to get the number of drops, then divide by the drops you get from each roll. Each drop is the ceiling height plus a trim allowance; A.S. Création advises adding about 5 cm so the cut is not too tight.
A pattern adds waste. With a straight match every drop starts at the same point of the design, so each drop is rounded up to whole repeats. With a half-drop match each drop starts half a repeat lower than the one beside it, so when you cut drops one after another the paper per drop is rounded up to end on a half repeat. Divide the roll length by the paper per drop and round down to get whole drops per roll, then divide the drops you need by that number and round up.
Doors and windows count only when they replace a whole drop. Their area is divided by the area of one full-height drop 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 drop for each wall.
drops = wall width ÷ roll width, rounded updrops saved = door and window area ÷ (roll width × wall height), rounded downcut length = wall height + trimpaper per drop, straight match = cut length rounded up to whole repeatspaper per drop, half-drop match = whole repeats + ½ repeat, at least the cut lengthdrops per roll = roll length ÷ paper per drop, rounded downrolls = (drops − drops saved) ÷ drops per roll, rounded upHow many drops do you get from a roll of wallpaper?
A 10.05 m roll gives 3 drops at a 2.5 m ceiling, the standard height Porter’s Paints uses, and 4 drops only on walls up to about 2.46 m high. A pattern repeat can cost a drop per roll on 2.4 m walls and on ceilings of 3 m or more.
| Wall height | No repeat | 53 cm straight match | 64 cm half-drop |
|---|---|---|---|
| 2.4 m | 4 | 3 | 3 |
| 2.5 m | 3 | 3 | 3 |
| 2.7 m | 3 | 3 | 3 |
| 3.0 m | 3 | 3 | 2 |
| 3.3 m | 3 | 2 | 2 |
Computed with the formulas above for a 530 mm × 10.05 m roll. No Australian maker page we opened states a roll length, so check the label and use Other size if yours differs.
How many rolls of wallpaper for a room?
A 4 × 3 m room with 2.5 m walls needs 9 standard rolls of plain paper. Every figure below assumes 10.05 m × 530 mm rolls, 5 cm of trim, one 900 × 2000 mm door, one 1200 × 1200 mm window and no pattern repeat.
| Room | 2.4 m walls | 2.5 m walls | 2.7 m walls |
|---|---|---|---|
| 3 × 3 m | 6 | 7 | 7 |
| 4 × 3 m | 7 | 9 | 9 |
| 4 × 4 m | 8 | 10 | 10 |
| 5 × 4 m | 8 | 11 | 11 |
| 6 × 4 m | 9 | 12 | 12 |
| 6 × 5 m | 10 | 14 | 14 |
A 2.4 m wall gets 4 drops per roll and a 2.5 m wall only 3, which is why that extra 10 cm of height adds up to 4 rolls in the largest room above. The door and window sizes are examples, not standard sizes; change them to match your room.
Worked examples
A 4 × 3 m bedroom with 2.5 m ceilings
The four walls add up to 14 m. With 530 mm rolls that is 14 ÷ 0.53 = 26.4, so 27 drops. The 900 × 2000 mm door and 1200 × 1200 mm window add up to 3.24 m², and one full-height drop covers 0.53 × 2.5 = 1.33 m², so the openings replace 2 whole drops, leaving 25.
Each drop is 2.5 m plus 5 cm of trim: 2.55 m. A 10.05 m roll gives 10.05 ÷ 2.55 = 3.9, so 3 drops per roll, and 25 ÷ 3 = 8.3, so you need 9 rolls. The wall area to cover is 31.8 m².
A 6 m feature wall, plain and with a half-drop pattern
Porter’s Paints works through a 6 m wall at a 2.5 m ceiling: 6 ÷ 0.530 = 11.3 drops, divided by 3 drops per roll is 3.7, so 4 rolls. In the calculator, choose Walls, enter 6 m, and set Doors and Windows to 0: it shows 12 drops, 3 per roll, 4 rolls.
Raise the ceiling to 3 m and choose a 64 cm half-drop pattern. Each drop needs 3.05 m, rounded up to 5 repeats plus half a repeat: 5 × 64 + 32 = 352 cm, or 3.52 m, of which 47 cm goes on lining up the pattern. A 10.05 m roll holds 2 of those drops, so the 12 drops need 6 rolls, against 4 rolls of plain paper at the same height.
Should you subtract doors and windows when measuring for wallpaper?
Subtract them only where they replace whole drops. Graham & Brown tells you to ignore doors and windows so that you end up ordering a little extra. Counting whole drops is a middle path: on 2.5 m walls, a 900 × 2000 mm door and a 1200 × 1200 mm window save 2 drops, or 2.65 m² of paper, rather than the full 3.24 m² they measure.
Before you start, check that every roll has the same batch number. Porter’s Paints says this keeps the colour and pattern consistent, so buy any spare roll in the same order rather than later.
Common questions
How many rolls of wallpaper do I need for a 4 × 3 m room?
You need 9 rolls of plain paper if the walls are 2.5 m high, with one door and one window, using 530 mm × 10.05 m rolls. The walls take 25 drops after the openings, and each roll gives 3 drops of 2.55 m. With 2.4 m walls each roll gives 4 drops, and the same room needs 7 rolls. A pattern repeat or a spare roll for repairs adds to these counts.
How many drops do you get from a roll of wallpaper?
You get 3 drops per roll at a standard 2.5 m ceiling, the figure Porter’s Paints gives. With a 10.05 m roll and 5 cm of trim, the count rises to 4 drops only on walls up to about 2.46 m high and stays at 3 up to 3.30 m. A pattern repeat makes each drop longer: a 64 cm half-drop at a 3 m ceiling leaves 2 drops per roll.
How wide is a roll of wallpaper in Australia?
Most standard rolls are 530 mm wide, according to Porter’s Paints, but widths vary: Porter’s own grasscloth is 910 mm wide. European makers give 10.05 m as the usual length, which gives the 3 drops per roll at a 2.5 m ceiling that Porter’s Paints quotes. Read the label for the exact width and length, and use Other size when your roll differs.
What is a half-drop match on wallpaper?
A half-drop match means each drop starts half a pattern repeat lower than the one next to it, so the motif on every second drop sits at the same height. Because alternate drops start at different points of the design, cutting them one after another uses more paper than a plain one. With a 64 cm repeat on 3 m walls, each drop takes 3.52 m of paper instead of 3.05 m.
How much extra wallpaper should I buy?
Allow about 10% extra, as Graham & Brown recommends, or at least one spare roll for mistakes and later repairs. Buy the spare in the same order, because rolls from the same batch number keep the colour and pattern consistent, according to Porter’s Paints. A roll bought months later may come from a different batch.
How much wallpaper paste do I need per roll?
Porter’s Paints counts 1.5 kg of its wallpaper paste per roll, so a 4 × 3 m room that needs 9 rolls takes about 13.5 kg. Other pastes cover a different number of rolls, so use the figure printed on the packet of the paste you buy.
Sources
- Porter’s Paints, How to estimate quantities (checked 19 October 2026)Rolls usually 530 mm wide, grasscloth 910 mm; 3 drops per roll at a standard 2.5 m ceiling; 6 m wall worked example; 1.5 kg of paste per roll; same batch number.
- Graham & Brown, How to measure for wallpaper (checked 19 October 2026)Ignore doors and windows when measuring; allow an extra 10% for waste.
- A.S. Création, Calculate wallpaper requirements (checked 19 October 2026)Euro roll 10.05 m × 0.53 m; add about 5 cm to the room height; a spare roll for repairs.
- Boråstapeter, Wallpaper calculator (checked 19 October 2026)Roll usually 10.05 m long and 53 cm wide; use the highest wall height when it varies.
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