How this calculator works + FAQs
Measure the room once and get a buying quantity you can trust. This calculator counts physical drops, rounds every cut to the pattern repeat, and totals walls separately so unusable corner offcuts are never treated as full coverage. Your result updates as you type and includes the spare roll that protects against damage and batch changes.
How to calculate wallpaper rolls
- Measure your walls. Enter each wall’s width and height (or the room perimeter and ceiling height).
- Set the pattern. Pick the match type and enter the pattern repeat from the roll label.
- Choose your roll. Select a roll preset (European, US double, peel & stick) or enter custom dimensions.
- Read the result. See rolls to buy, cost and paste, with a per-wall breakdown and diagram.
- Buy one batch. Order every roll in one purchase with the same batch number, plus one spare.
A worked example
For a 12 m perimeter with 2.4 m walls, a 52 cm straight repeat and a standard 53 cm × 10.05 m roll, each drop is rounded to 2.60 m. Three drops fit per roll and 23 drops cover the room, so the base is 8 rolls. A 10% buffer rounds that to 9; one repair roll makes the buy quantity 10.
Use this calculator for
- Whole-room orders. Turn a perimeter and ceiling height into a safe roll quantity before placing one dye-lot order.
- Feature walls. Switch to per-wall mode for one focal wall and see every drop and seam in the elevation drawing.
- Patterned papers. Account for straight, half-drop and stated-offset matches instead of relying on a crude area estimate.
- Store-ready lists. Add the roll price, copy the shopping list and print the diagram to take with you.
- US and European rolls. Compare metric rolls with US single-roll equivalents and double-roll bolts without mixing labels.
Frequently asked questions
How many rolls of wallpaper do I need?
Count the full-height drops needed across each wall, divide by the whole drops that fit on one roll, and round up wall by wall. Then add your safety buffer and a repair roll. This calculator performs those steps with your actual pattern repeat and roll size.
Why is strip counting better than wall area?
A roll can have enough total area but still be unable to yield another full-height drop. Strip counting models the pieces you can physically cut, including pattern alignment, so it avoids the under-ordering hidden by area-only math.
Should I include doors and windows?
Usually leave small openings in the estimate because wallpaper is hung across them and trimmed, and those offcuts are rarely reusable. The advanced opening option removes whole drops only for large openings.
How much extra wallpaper should I buy?
The default adds a transparent 10% handling and measurement buffer, then one separate repair roll. Complex rooms or inexperienced installers may justify a larger buffer, while the pattern-repeat waste is already calculated in each cut.
What is a wallpaper batch or dye lot?
A batch or dye lot is one production run. Colour can vary slightly between runs, so buy the entire quantity at once, confirm every label has the same batch number, and keep the spare roll for future repairs.
Does the calculator work in feet and metres?
Yes. You can measure in imperial or metric while the engine keeps one metric calculation internally, preventing the rounding drift that comes from mixing roll-label units.