Wallpaper calculator
Wallpaper can't be calculated on area alone: each strip runs the full height of the wall, and the offcut left at the end of a roll is usually too short for another strip. That's why the reliable method counts strips, not square metres.
Enter the room's dimensions and the roll details from the label. For patterned wallpaper, add the pattern repeat so each strip can be cut long enough to line up with the next.
Your measurements
Result
- Strips needed
- 25 pcs
- Strips per roll
- 3 pcs
- Rolls to buy
- 9 pcs
Buy all rolls with the same batch number — shades can differ between batches.
How the calculation works
- Room perimeter = 2 × (length + width).
- Doors and windows are converted into wall width: their area ÷ wall height, subtracted from the perimeter.
- Strips needed = remaining perimeter ÷ roll width, rounded up.
- Strips per roll = roll length ÷ (wall height + pattern repeat), rounded down to whole strips.
- Rolls = strips needed ÷ strips per roll, rounded up.
Worked example
A 4 × 3 m room has a 14 m perimeter. The 3 m² of doors and windows, at 2.6 m wall height, take away about 1.15 m of wall, leaving roughly 12.85 m. With 53 cm rolls you need 25 strips. A standard 10.05 m roll gives 3 strips of 2.6 m (the remaining 2.25 m is too short for a fourth), so you need 25 ÷ 3 = 8.3, which means 9 rolls.
What the calculator assumes
- Offcuts from the end of a roll don't make full strips — which is why the calculation works in strips.
- With patterned wallpaper each strip is cut longer by the pattern repeat so the design lines up; the repeat is printed on the label.
- Short pieces above doors and windows are usually cut from offcuts.
When to adjust the result
- Wide rolls (70 or 106 cm) need fewer strips, but are heavier to hang and harder to handle around corners.
- A drop-match (offset) pattern can waste more than the repeat value suggests; buy one extra roll for complicated patterns.
- Buy all rolls with the same batch number — shades can differ between batches.
Frequently asked questions
How many strips do I get from one roll?
Divide the roll length by the wall height plus the pattern repeat and round down. A 10.05 m roll gives 3 strips for a 2.6 m wall without a pattern, and only 3 strips — not 4 — even though the roll is longer than 3 × 2.6 m.
What is a standard wallpaper roll size?
In Europe the most common roll is 53 cm wide and 10.05 m long (about 5.3 m²). Wider 70 cm and 106 cm rolls are common for non-woven wallpaper. American rolls are often sold as double rolls, so always check the label.
Should I buy an extra roll?
For patterned wallpaper or rooms with many openings, one extra roll is a good idea — a later roll from a different batch may not match.