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Generator Hut

Wallpaper Calculator

Rolls of wallpaper for a room, pattern repeat included.

Your measurements

A standard European roll is about 33 ft.

Commonly 20.5 in for European rolls, 27 in for American.

Zero for a plain paper. A large repeat wastes a lot of length per strip.

Wallpaper required

8rolls

8 rolls — 29 strips

Strips needed48 ft perimeter at 20.5 in wide
29
Length per stripno pattern repeat allowance
8 ft
Strips per rollfrom a 33 ft roll
4
Rolls to buy
8

Pattern repeat is the input people forget and it is expensive. A large repeat means every strip has to start at the same point in the pattern, so the offcut at the top of each drop is wasted — a 21 inch repeat can cost you a whole extra roll on an average room.

No deduction is made for doors and windows. Paper is hung over openings and trimmed, and the offcuts around them are rarely long enough to reuse.

Buy every roll from the same batch number and check it on delivery. Colour varies between print runs and the difference is obvious where two strips meet.

Enter the room perimeter and height along with the roll dimensions, and crucially the pattern repeat. The repeat is the input most calculators omit and the one most likely to leave you a roll short — a large repeat wastes real length on every single drop.

Why use this tool?

Pattern repeat accounted for

Every strip must start at the same point in the pattern, so the offcut at the top of each drop is wasted. A 21 inch repeat can cost a whole extra roll.

Any roll size

European rolls are typically 20.5 inches by 33 feet, American ones 27 inches. Both are catered for.

Strips shown too

The strip count is what you check against the walls, the roll count is what you buy.

No opening deductions

Paper is hung over doors and windows and trimmed, matching how the job is actually done.

How this wallpaper calculator works

The number of strips is the room perimeter in inches divided by the roll width, rounded up. Each strip has to be at least as long as the wall is high, plus an allowance equal to the pattern repeat so the design can be aligned with its neighbour.

Strips per roll is the roll length divided by that per-strip length, rounded down — you cannot use part of a strip. Rolls needed is then the strip count divided by strips per roll, rounded up.

That double rounding is why the repeat matters so much. On an 8 foot wall a 33 foot roll yields four strips with no repeat, but only three once a 21 inch repeat is added — a 25 per cent drop in yield from a single input.

How to use it

  1. Step 1: Measure the perimeter

    Around the whole room including doors and windows. Paper is hung over openings and cut out afterwards.

  2. Step 2: Enter the wall height

    Floor to ceiling, or the height of the papered section if you are working above a dado.

  3. Step 3: Find the pattern repeat

    Printed on the roll label, usually in inches or centimetres. Enter zero for a plain or random-match paper.

  4. Step 4: Check the batch numbers

    On delivery, before hanging. Colour varies between print runs and the difference shows where two strips meet.

Example usage

A plain paper in a standard room
A 48 foot perimeter needs 29 strips at 20.5 inches wide. With no repeat, a 33 foot roll yields 4 strips from an 8 foot wall, so 8 rolls.
The same room with a 21 inch repeat
Each strip now needs 9.75 feet rather than 8, so a roll yields 3 strips instead of 4. The order rises from 8 rolls to 10 — the repeat alone costs two rolls.
A feature wall
A single 12 foot wall needs 8 strips. Even at 4 strips per roll that is 2 rolls, and a feature wall is exactly where a large repeat is most likely.

Frequently asked questions

How many rolls of wallpaper do I need?

Divide the room perimeter by the roll width to get strips, work out how many full strips a roll yields at your wall height, then divide. A standard room typically takes 8 to 12 rolls depending on the pattern repeat.

What is a pattern repeat and why does it matter?

It is the vertical distance before the design starts again. Every strip must begin at the same point in the pattern, so the offcut at the top of each drop is wasted. A large repeat can reduce a roll's yield by a quarter or more.

Should I deduct doors and windows?

No. Paper is hung across openings and trimmed out afterwards, and the offcuts around them are rarely long enough to use elsewhere. Deducting them tends to leave you short.

Why do batch numbers matter?

Wallpaper is printed in batches and colour varies measurably between runs. Two rolls from different batches meeting on the same wall show a visible line. Check every roll on delivery, not when you start hanging.

Should I buy an extra roll?

Usually yes, especially with a large repeat where the arithmetic is least forgiving. An unopened roll can often be returned; a discontinued pattern cannot be matched later.

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