Wallpaper calculator

Wallpaper is bought in strips, and the pattern repeat changes everything. This counts strips per roll the way a hanger does, so you order the right number the first time.

On the label. 0 for solids and random match.

Calculator last reviewed 2026-09-03. How we calculate.

How this calculator works

Wallpaper is bought in strips, not square feet — a roll that "covers 56 sq ft" only does so if every strip comes out of it whole. So this calculator counts strips. Each strip must be the wall height plus the pattern repeat (you lose up to one repeat aligning each strip) plus 4 inches of trim. Strips per roll is the roll length divided by that strip length, rounded down. Strips needed is the wall perimeter divided by the roll width, rounded up. Doors and windows are not subtracted from the strip count because you still hang a full-width strip around them; the paper you cut out is waste. Rolls is strips needed divided by strips per roll, rounded up.

strip_length = height + repeat/12 + 0.33 ft
strips_per_roll = ⌊ roll_length ÷ strip_length ⌋
rolls = ⌈ (perimeter × 12 ÷ roll_width) ÷ strips_per_roll ⌉

Frequently asked questions

How many square feet does a double roll of wallpaper cover?

A standard American double roll is 20.5" wide by 33 ft long, about 56 sq ft gross. With an 8-ft wall and no pattern repeat you get 3 full strips per roll, roughly 41 sq ft of usable coverage. A large repeat can cut that to 2 strips.

Why do I need to know the pattern repeat?

Every strip has to line up with the one before it, so you slide each strip up or down by as much as one repeat before cutting. A 24" repeat on an 8-ft wall turns a 3-strip roll into a 2-strip roll. The repeat is printed on the label.

Should I subtract doors and windows?

Not for strip count. You hang a full-width strip beside a door and cut the opening out, so the roll is consumed either way. Only a very wide opening (a patio slider, a pass-through) saves a whole strip.

Is peel-and-stick easier to estimate?

Peel-and-stick rolls are shorter (often 18 ft), so you get fewer strips per roll and need more rolls for the same wall. The calculator has a peel-and-stick roll size built in.

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