Wallpaper Calculator

Wallpaper is the material most often under-bought, because the naive calculation — wall area divided by roll coverage — ignores the thing that actually eats paper: pattern matching. Every drop must start at the same point in the design, so offcuts from the top of one strip cannot be used at the bottom of the next.

The calculator handles this by rounding each drop up to a whole pattern repeat before dividing by roll coverage. That is why a large floral with a 24 inch repeat can need two more rolls than a plain texture for the exact same room.

How this calculator works

Every field is editable and the result updates as you type — nothing is submitted anywhere, all the maths runs in your browser. That matters for a number you are about to spend money on: you can see exactly which input moved the answer, and by how much.

What this calculation assumes

Assumes a straight match, all four walls treated as solid, and no deduction for doors or windows. Half-drop and random matches waste differently — check the match type on the roll label before ordering.

Treat the result as an order-of-magnitude check rather than a final quantity. Product packaging changes, regional labour rates vary by a factor of two, and no calculator has seen your actual site.