Wallpaper Calculator

About This Tool

Wallpaper transforms a room like few other design elements can, but ordering the wrong amount leads to either wasted money or a stressful mid-project shortage. This calculator accounts for the most common variables that affect coverage: room dimensions, doors and windows, roll specifications, and pattern repeat, which is the most commonly overlooked factor.

Understanding Pattern Repeat

Pattern repeat is the vertical distance between one point in a pattern and the identical point above it. A 21-inch repeat means you must align each strip so the pattern matches, creating waste at the top or bottom of each strip. Large pattern repeats (18-24 inches) can increase material needs by 15-25%. Solid or textured wallpapers with no pattern repeat are the most economical and easiest to install.

Standard Roll Sizes

In the US, a standard single roll is 20.5 inches wide by 33 feet long, covering approximately 56 square feet. A double roll (most common at retail) is 20.5 inches by 33 feet. European rolls are typically 21 inches wide by 33 feet. Some designer and grasscloth wallpapers come in 27-inch or 36-inch widths. Always check the roll dimensions on the product specifications, as there is significant variation between brands.

Tips for Ordering

Always buy all rolls from the same dye lot (batch number) to ensure consistent color. Order at least 1-2 extra rolls beyond what the calculator suggests for insurance against mistakes and future repairs. Many retailers accept returns of unopened rolls. If your room has unusual features like alcoves, sloped ceilings, or half-walls, measure those areas separately.