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Wallpaper Calculator

Estimate single rolls of wallpaper for a room, with doors and windows removed.

Wallpaper is sold in rolls, priced per roll, and almost always patterned — which means offcuts. Ordering too few rolls risks a dye-lot mismatch when you reorder; ordering far too many wastes money on a product most stores will not take back once opened. This calculator works out the net wall area of your room and converts it into single rolls using a realistic usable coverage per roll.

A standard single roll contains about 56 square feet of paper, but after trimming and pattern matching, only around 30 square feet typically ends up on the wall. Large pattern repeats waste more, so for a bold repeat choose a lower usable coverage in your planning and keep one spare roll for future repairs.

How to use this calculator

1. Measure the room and count doors and windows, exactly as you would for paint.
2. Look at the pattern repeat on the wallpaper you have chosen — the bigger the repeat, the less usable coverage per roll.
3. Select the matching usable coverage value and calculate.
4. Add one spare roll from the same dye lot for repairs; you cannot buy a matching roll years later.

How wallpaper rolls are calculated

Net wall area = 2 x (length + width) x height, minus doors and windows. Rolls = net area / usable coverage per roll. Usable coverage — not the printed roll area — is the honest number, because every drop must be cut longer than the wall and the pattern aligned with its neighbour, which turns the trimmings into waste.

Common mistakes to avoid

• Dividing the wall area by the full 56 sq ft printed on the roll and ordering half of what the job needs.
• Ordering rolls weeks apart so the second batch comes from a different dye lot with a slightly different colour.
• Forgetting chimney breasts, alcoves and the wall above a picture rail — measure every surface that will be papered.

Frequently asked questions

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