Wallpaper Calculator
Measure your walls, enter the roll size and pattern repeat printed on your wallpaper, and get the number of rolls to buy.
How we calculate this
We multiply wall width × height × number of walls for the total wall area, subtract about 20 ft² (1.9 m²) per door and 15 ft² (1.4 m²) per window, then work out how many full-height strips come out of one roll. With a straight match each strip is cut up to the next whole pattern repeat; with a drop match we allow an extra half repeat; with a random match (or no repeat) we use the full roll length. Strips per roll × roll width × wall height gives the usable coverage per roll, and we divide the net wall area by that, add your waste percentage, and round up to whole rolls.
Tip: Buy every roll in one go and check the batch number on each label — colours can shift noticeably between print batches.
Assumptions & things to watch
- Roll sizes, coverage and pattern repeats vary by product — the figures used here are the ones you entered from your wallpaper label, not an industry standard.
- Assumes full-height strips with no strip reused above a door or window; short offcuts over openings can save a roll on some rooms.
- Each door counts as about 20 ft² (1.9 m²) and each window about 15 ft² (1.4 m²). Enter fewer or more openings if yours are unusually sized.
- Actual coverage depends on the wallpaper, your wall condition and how the pattern lands, so treat the result as a practical estimate.
Estimates only — always double-check quantities with your supplier before ordering.
Quick tips: Wallpaper
How many rolls of wallpaper do I need?
It depends entirely on the roll size and pattern repeat of the paper you've chosen. Measure your walls, enter the roll width, roll length and repeat from the label, and this calculator works out the strips per roll and the rolls needed.
What is a pattern repeat?
The vertical distance before the design starts again. On a patterned paper each strip has to be cut at a whole number of repeats so the design lines up, which is why a big repeat means more waste and more rolls.
What's the difference between straight match and drop match?
With a straight match the pattern lines up at the same height on every strip. With a drop match alternate strips are dropped by half a repeat, so you lose a little extra length on each cut.
How much extra wallpaper should I order?
10% is a sensible allowance on plain walls. Go to 15–20% for a large repeat, alcoves, chimney breasts or sloping ceilings, and keep any spare roll for future repairs.
Do I subtract doors and windows?
Yes, but conservatively. This calculator deducts the opening area while still assuming full-height strips, because you usually can't reuse the offcut from above a door anywhere else.