Wallpaper Calculator

Find out how many rolls of wallpaper you need for a room. Enter the room perimeter (or let it add up your wall widths), the wall height, and the pattern repeat, and it works out the drops, the rolls, and a sensible waste allowance. Updates as you type.

How it works

• Drop length = wall height + pattern repeat (you lose up to one repeat per drop matching the design).
• Drops per roll = roll length ÷ drop length, rounded down (you can't use a part drop).
• Drops needed = room perimeter ÷ roll width, rounded up.
• Rolls = drops needed ÷ drops per roll, rounded up — plus your spare rolls.
• Buy spare from the same batch number so the colour matches.

FAQ

How do I calculate how many rolls of wallpaper I need?

Measure the total width of the walls (the perimeter) and the wall height. Work out how many full-height drops you can cut from one roll, then how many drops you need to go around the room, and divide. A standard roll is about 10 m long and 0.53 m wide. This calculator does the maths and adds an allowance for pattern matching and waste.

How long and wide is a standard roll of wallpaper?

A standard European roll is about 10 metres (33 ft) long and 0.53 metres (21 inches) wide, covering roughly 5 m² before waste. This calculator uses that roll by default and lets you change it if yours differ.

What is a pattern repeat and why does it matter?

The pattern repeat is the vertical distance before the design repeats. With a patterned paper you line up the design between drops, which wastes paper at the top of each length — bigger repeat, more waste. A plain paper (repeat 0) has almost no matching waste and needs fewer rolls.

Should I buy an extra roll of wallpaper?

Yes — always buy at least one extra, ideally with the same batch number. Dye lots vary between batches, so matching later is hard, and you'll want spare for mistakes and future repairs. The spare-rolls field defaults to 1.

Do I subtract doors and windows?

For a rough estimate it's safest not to — the offcuts around openings are often unusable and the spare covers mistakes. For very large openings you can reduce the perimeter a little. This calculator uses the full perimeter, which is the cautious, run-out-proof approach.

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