Wallpaper Roll Calculator

About this calculator

Wallpaper is sold in standard rolls — most commonly around 21 inches (53 cm) wide and 33 feet (10 m) long in the US/European "single roll" format, covering roughly 56 square feet (5.2 m²) of wall before trimming. Because pattern repeats force you to cut and discard matched sections, and because doors, windows and corners create waste, installers add a buffer — typically 10-15% — on top of the raw wall area calculation.

The basic method multiplies wall width by height to get total area, subtracts large openings if you want to be precise (many installers skip this and treat it as extra safety margin), divides by the coverage per roll, and rounds up. Painters and DIY renovators use this before a shopping trip because rolls from the same dye lot can run out mid-project, and buying short means a mismatched batch later.

This calculator takes your wall dimensions and applies a 10% waste allowance to tell you how many full rolls to buy.