Wallpaper Calculator
Counted in drops, which is how it is actually hung.
Work out Wallpaper. Counted in drops, which is how it is actually hung. Counts the thing everyone forgets to count.
Add up all four walls. Do not subtract doors and windows — the offcuts rarely reuse.
0 for plain paper. A large repeat can cost you a whole roll.
Rolls needed
9 rolls
34 drops at 4 per roll · 6.0% waste
Wallpaper is calculated in drops, not area. A roll yields a whole number of full-height drops and the remainder is offcut, so an area-based estimate under-orders almost every time. A pattern repeat is the expensive part. Each drop must be cut long enough to align the pattern, which can drop a roll from four usable lengths to three — a 25% increase in rolls from a change that looks cosmetic. Buy all rolls from the same batch. Batch numbers matter because colour shifts noticeably between print runs, and a mismatched roll halfway along a wall cannot be hidden.
How the Wallpaper Calculator works
Enter room perimeter, wall height and pattern repeat for the rolls needed. Calculated in drops rather than area, because a roll yields a whole number of full-height lengths and the remainder is offcut.
Also known as: how many rolls of wallpaper do i need · wallpaper rolls per room · pattern repeat wallpaper calculator · wallpaper estimator
Frequently asked questions
How many rolls of wallpaper do I need?
Work in drops. Divide the perimeter by the roll width for the number of drops, divide the roll length by your drop length for drops per roll, then divide one by the other and round up.
Why not just use the wall area?
Because a roll cannot be used down to the last centimetre. If a roll gives four usable drops and you need nine drops, you need three rolls — an area calculation would suggest fewer and leave you short.
How much does a pattern repeat cost me?
Potentially a whole roll. Each drop must be cut long enough to align the pattern, and a large repeat can take a roll from four usable drops to three — a 25% increase from something that looks purely cosmetic.
Should I subtract doors and windows?
Usually not. The offcuts around openings rarely reuse elsewhere, and running short mid-wall is far more expensive than one spare roll.
Put this calculator on your own site
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<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/wallpaper-calculator" style="color:#64748b">Wallpaper Calculator</a> from The Calc Library</p>The only condition is that the credit line below the frame stays in place. That one line is what pays for the tool being free — it is how anyone else finds it.