4 m × 3.5 m room, plain paper
Input Room 4 m × 3.5 m, height 2.5 m, openings 3.6 m², no repeat, 0.53 m × 10 m rolls.
Result 29 strips, 4 per roll, so 8 rolls covering 33.9 m² of wall with 42.4 m² of paper.
Wallpaper Calculator
Home & RenovationTurn room size and wall height into strips, rolls and wall area — with a pattern repeat allowance.
Your inputs
Result
Rolls to buy
—
- Strips needed —
- Paperable wall area — m²
- Paper bought — m²
Change any input and the result updates instantly.
Formula and rules
- Perimeter = 2 × (room length + room width)
- Strips = perimeter ÷ roll width, rounded up
- Cut height = wall height + pattern repeat
- Strips per roll = roll length ÷ cut height, rounded down
- Rolls = strips ÷ strips per roll, rounded up
- Wall area = perimeter × height − doors and windows
Worked examples
Same room with a 32 cm repeat
Input Same room, pattern repeat 32 cm.
Result Cut height rises to 2.82 m, only 3 strips fit per roll, so the job needs 10 rolls.
FAQ
Should I deduct doors and windows?
Deducting is optional. Because strips run the full height, the offcut above a door is rarely usable, so most decorators buy for the full wall and keep the spare for repairs.
Why does a pattern repeat add so many rolls?
Every strip must be cut long enough to match the pattern, so the usable length of each roll drops. A 32 cm repeat on a 2.5 m wall leaves 2.82 m per strip and often only three strips per roll.
How much extra should I keep?
Buy one extra roll when the pattern is large or the room has many corners. The same dye lot rarely comes back, and a spare roll fixes future damage invisibly.
Disclaimer: Results follow the formula shown on this page and are for reference only. Real-world quantities vary with materials, technique and conditions, so allow a margin before ordering.