Wallpaper Calculator
Estimate how many rolls of wallpaper a room needs from the wall area and roll coverage.
Rolls needed7rolls
Rolls before waste6rolls
Area with waste34.50m²
Rolls needed = wall area × (1 + waste ÷ 100) ÷ coverage per roll, rounded up. A standard roll covers about 5 m² of usable wall once trimmed. For 30 m² of wall with a 15% waste allowance: 30 × 1.15 ÷ 5 = 6.9, rounded up to 7 rolls. Patterned papers need more waste so the repeat lines up — buy all rolls from the same batch.
Questions
How many rolls of wallpaper do I need?
Multiply the wall area by your waste allowance, divide by the coverage per roll, then round up. 30 m² with 15% waste and 5 m² rolls needs 7 rolls.
Why allow extra for patterned wallpaper?
Patterns must line up between strips, so you trim and discard part of each drop to match the repeat. Allow 15% or more and buy from one batch for a consistent colour.