Count drops, not square feet
Wallpaper is hung in vertical strips called drops. Each drop is cut from one roll, and the piece left at the end of a roll is usually too short for another drop. That’s why this calculator counts whole drops instead of dividing the wall area by the roll’s coverage, which can come up short.
- Drops needed. Total wall width ÷ roll width, rounded up.
- Drop length. Wall height + trim allowance + pattern repeat allowance.
- Drops per roll. Roll length ÷ drop length, rounded down.
- Rolls. Drops needed ÷ drops per roll, rounded up. Add a spare if you like.
Example: 3.3 m of wall, 2.2 m high, with 52 cm × 10 m rolls and no repeat. That’s 7 drops of 2.3 m (with 10 cm trim), 4 drops per roll, so 2 rolls, or 3 with a spare.
Pattern repeat and match
The pattern repeat is the distance before the design starts again; it’s printed on the label or sample. Matching the pattern from one drop to the next uses extra paper, so the calculator adds:
- Free match (stripes, plains): nothing extra.
- Straight match: one repeat per drop.
- Half-drop match: one and a half repeats per drop, following Fabrics & Papers’ extra half-repeat allowance.
This is a conservative allowance applied to every cut drop, including the first. It estimates a purchase quantity rather than an optimized cutting sequence; follow the hanging instructions for your chosen paper.
Roll sizes
| Roll | Size | Notes |
|---|---|---|
| European roll | 52 or 53 cm × 10 m | About 5.3 m² (57 sq ft) |
| US double roll | 20.5 to 27 in × 27 to 33 ft | About 56 to 70 sq ft |
US wallpaper is often priced per single roll but sold as a double roll, so check what one unit means before you order. Pick “Other size” to enter the exact width and length from your label.
Before you buy
- Add the widths of walls that share the same height, and calculate walls of a different height (such as above a staircase) separately.
- Doors and windows aren’t subtracted. The extra helps with cutting around them.
- Farrow & Ball suggests adding one more roll for trimming or mistakes. Buy every roll with the same batch number, as color can vary between batches.
Keep your plan
Print your current plan or choose Save as PDF in the browser’s print dialog. Your inputs stay in a device draft when browser storage is available. An optional free account lets you save and sync the project in My projects. Calculating and printing stay open to everyone.