Where do I find roll length, roll width, and pattern repeat?

Every wallpaper package lists these on the label. US “double rolls” are typically 33 ft × 1.75 ft (21 in); European rolls are 10 m × 0.53 m.

Why does the calculator round up so aggressively?

Each strip must be cut from a single roll — you can’t splice two short pieces. Rounding strips-per-roll down (floor) and rolls needed up (ceil) is the only safe approach.

What is a pattern repeat?

A vertical pattern repeat is how often the design repeats top-to-bottom. For pattern-matched walls you waste material equal to one repeat per strip; the tool adds that to your strip length.

Does it account for half-drop patterns?

Half-drop patterns waste only half a repeat per strip; enter half your repeat size if the package indicates a half-drop match.

How much waste should I plan for?

Plain wallpaper: 10%. Plain with a repeat: 15%. Heavy patterns or odd angles: 20%+. The tool defaults to 15% which works for most jobs.

Wallpaper Calculator

Calculate wallpaper rolls from room dimensions, roll size, pattern repeat, and waste factor.

Written by Golam Rabbani, Founder & Lead Engineer

This interactive tool requires JavaScript. Read the formula and worked example below; you can compute the result by hand.

How to use this wallpaper calculator

Pick imperial (ft) or metric (m) at the top.
Enter the room length, width, and ceiling height.
Set the number of doors and windows so the tool can subtract them.
Enter the roll length and roll width from the wallpaper package label.
If the pattern has a vertical repeat, enter it; otherwise leave it at 0.
Adjust waste % (default 15) and press Calculate to get the number of rolls.

About this wallpaper calculator

The wallpaper calculator counts how many full vertical strips of paper fit in one roll for your ceiling height plus the pattern repeat, then divides the room perimeter by the strip width to find how many strips you need, then divides strips needed by strips per roll. It deducts a standard area per door and window from the gross wall area for reporting only, then adds your waste percentage on top of the raw roll count.

Example: a 12 ft × 10 ft room with 8 ft ceilings, 1 door, 2 windows, a standard US double roll (33 ft × 1.75 ft), 2-inch (0.17 ft) pattern repeat, and 15% waste. Perimeter = 2(12 + 10) = 44 ft. Strip length = 8 + 0.17 = 8.17 ft → strips per roll = floor(33 / 8.17) = 4. Strips needed = ceil(44 / 1.75) = 26. Raw rolls = ceil(26 / 4) = 7. Add 15% waste → 7 × 1.15 = 8.05, ceil → 9 rolls. The status panel also reports the net wall area (44 × 8 − 21 − 30 = 301 ft²) for context.

Always buy a little extra and keep one full roll for repairs — if a strip is damaged later, dye-lot matching across batches is rarely possible.

FAQ

Where do I find roll length, roll width, and pattern repeat?: Every wallpaper package lists these on the label. US “double rolls” are typically 33 ft × 1.75 ft (21 in); European rolls are 10 m × 0.53 m.
Why does the calculator round up so aggressively?: Each strip must be cut from a single roll — you can’t splice two short pieces. Rounding strips-per-roll down (floor) and rolls needed up (ceil) is the only safe approach.
What is a pattern repeat?: A vertical pattern repeat is how often the design repeats top-to-bottom. For pattern-matched walls you waste material equal to one repeat per strip; the tool adds that to your strip length.
Does it account for half-drop patterns?: Half-drop patterns waste only half a repeat per strip; enter half your repeat size if the package indicates a half-drop match.
How much waste should I plan for?: Plain wallpaper: 10%. Plain with a repeat: 15%. Heavy patterns or odd angles: 20%+. The tool defaults to 15% which works for most jobs.