Wallpaper Calculator
Free wallpaper calculator. Estimate how many wallpaper rolls you need by room size and pattern repeat. No signup.
What is a wallpaper calculator?
A wallpaper calculator estimates how many rolls you need to paper a room’s walls, based on wall area, roll dimensions, and pattern repeat. It works out how many full-height strips each roll yields — the real constraint on roll count.
How this calculator works
- Enter the room length, width, and wall height, plus roll width and length.
- It computes the perimeter and divides by roll width to find strips needed.
- Each roll’s strips are counted by floor(roll length ÷ drop length).
- A pattern repeat increases the drop length, because each strip must align to the print.
How to use the result
- Add 6 inches per drop for trimming at the ceiling and baseboard — the calculator includes it.
- Enter the pattern repeat if your wallpaper has one; matching eats the most material.
- Buy one extra roll for mistakes, matching errors, and future repairs.
- Confirm whether you’re buying single or double rolls — many wallpapers sell by the double roll but list per single.
How many rolls of wallpaper do I need?
A 12×10 ft room with 8-foot walls is about 352 ft² of wall — roughly 26 strips. At 21″ × 33 ft rolls (about 3 strips per roll), that’s around 9 rolls, or 4–5 double rolls. Pattern repeats push it higher: a 12-inch repeat adds meaningful waste per strip.
Common mistakes
- Dividing wall area by roll area. Pattern matching means you can’t use a roll’s full length — strip counting is the accurate method.
- Ignoring the pattern repeat. A large repeat can raise roll count by a third or more.
- Forgetting doors and windows. Subtract them only if they’re large; small openings are often papered around and cost little.
Wallpaper hangs on the same walls the paint calculator covers — pick one finish and measure once. If you’re redoing the surfaces underneath first, the drywall calculator prices the new sheets.