Wallpaper Rolls Calculator

How this calculator works

Drop length = wall height, rounded up to the next full pattern repeat if a repeat is set. Drops per roll = floor(roll length / drop length). Strips = round up[(net wall area / wall height) x waste factor / roll width]. Rolls = round up(strips / drops per roll).

Worked example

A 4 m x 3 m room with 2.4 m walls, one door, two windows, a standard 10.05 m x 0.53 m roll, and no pattern repeat needs 4 drops per roll and 7 rolls after openings and 10% waste.

Assumptions to check

The default UK roll size is 10.05 m x 0.53 m ("standard" roll); many US rolls differ - update rollLength/rollWidth for the product you are buying.
A pattern repeat rounds each drop up to the next full repeat, which uses more paper than a plain pattern - set repeat to 0 for a plain or random-match paper.
Trimming, matching at corners, and leftover offcuts are covered by the waste allowance, not modeled strip-by-strip.

Read the calculation and QA methodology →

FAQ

What is a pattern repeat?

The vertical distance before a wallpaper design repeats. Papers with a repeat need each drop cut longer than the wall height so the pattern lines up between strips, which uses more rolls than a plain paper.

Do I need extra for a chimney breast or alcove?

Yes - the "length" and "width" here model a simple rectangular room. Add extra strips manually for chimney breasts, bay windows, or unusual room shapes.

Why not just divide wall area by roll area?

Rolls are cut into whole drops, and pattern repeat and trimming waste mean a roll rarely papers its full nominal area - counting drops and strips gives a realistic order quantity.