Wallpaper Calculator — How Many Rolls Do I Need?
Wallpaper math is trickier than paint — pattern repeats eat whole strips. Enter your wall and roll below for an exact roll count, rounded up to full rolls. Free, instant, no signup.
Quick answer
Divide your wall width (in inches) by the roll width for strips needed, then divide the roll length by one strip length (wall height rounded up to the nearest pattern repeat) for strips per roll. A 12-ft accent wall with 8-ft ceilings typically needs 2–3 double rolls.
US standard rolls are 20.5" × 33 ft. With a pattern, each strip wastes one full repeat to line the design up.
Your wallpaper estimate
Rolls to buy
2
8 strips needed · 4 strips per roll
- Total width to cover
- 12.0 ft
- Strip length (with repeat)
- 96 in
Rounded up to full rolls — and grab one extra roll from the same dye lot for future repairs.
How the calculation works
Pros calculate wallpaper in strips, not square feet — because every strip must run full height and patterns must align:
- Total width: add up the width of every wall you're papering, in inches.
- Strips needed: total width ÷ roll width, rounded up. A 144" wall with 20.5" rolls needs 8 strips.
- Strips per roll: roll length ÷ (wall height + one pattern repeat). The repeat is pure waste — it's the price of lining the design up.
- Rolls: strips needed ÷ strips per roll, rounded up to whole rolls. You can't buy half a roll.
Common US roll sizes
| Roll type | Size | Coverage (no pattern) |
|---|---|---|
| US double roll | 20.5" × 33 ft | ~56 sq ft |
| US single roll | 20.5" × 16.5 ft | ~28 sq ft |
| Euro roll | 21" × 33 ft | ~57 sq ft |
| Wide-width | 27" × 27 ft | ~60 sq ft |
Always check your actual roll — boutique brands love odd sizes.
Tips from the pros
- Buy one extra roll, same dye lot. Color varies between print runs — a later roll may not match.
- Start in the least visible corner. Your last strip rarely matches the first perfectly; hide the seam behind a door.
- Big patterns = big waste. A 24" repeat can add 1–2 extra rolls versus a plain paper on the same wall.
- Number your strips as you cut them — it keeps the pattern sequence straight on long walls.
- Keep scraps. A labeled leftover roll is the fastest fix for a torn corner years later.