Wallpaper Calculator: How Many Rolls Do I Need?

To calculate wallpaper rolls, count strips, not square feet:

1. Strips needed = wall width (inches) ÷ roll width, rounded up.
2. Cut length = wall height + 4 in for trimming, rounded up to a whole pattern repeat.
3. Strips per roll = roll length ÷ cut length, rounded down.
4. Rolls = strips needed ÷ strips per roll, rounded up.

For a typical 12 × 14 ft room with 8 ft walls and one door, that's 29 strips → 10 double rolls of 20.5 in × 33 ft wallpaper. A large pattern repeat can push it much higher (worked example below).

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The strip method, step by step

1. Measure each wall's width in inches and add them up (the room's perimeter). Subtract full-height openings such as doors and closet openings. Don't subtract windows unless they're very large, because you'll still need strips above and below them.
2. Strips needed = total width ÷ roll width, rounded up.
3. Cut length = wall height + 4 inches (about 2 in at the top and 2 in at the bottom for trimming, per York Wallcoverings' guidance).
4. Pattern repeat: for straight-match or drop-match papers, round the cut length up to a whole number of repeats so each strip starts at the same point in the pattern. Random-match papers (textures, stripes) don't need this.
5. Strips per roll = roll length (in inches) ÷ cut length, rounded down. Leftover pieces usually aren't full height.
6. Rolls = strips needed ÷ strips per roll, rounded up. Add one roll for mistakes and future repairs if the paper is expensive or hard to reorder.

Check the roll label for width, length, repeat and match type. A common double roll is 20.5 in × 33 ft (about 56 sq ft), while a single roll is about half that. Other widths exist.

How many rolls of wallpaper do I need? Room-size chart

8 ft walls, 20.5 in × 33 ft double rolls, one 36 in door subtracted, windows not subtracted, little or no repeat (3 strips per roll):

With 33 ft rolls, you get 3 full strips per roll as long as the cut length is 132 in (11 ft) or less. Once a tall wall or a big repeat pushes the cut length over 132 in, you only get 2 strips, and the roll count jumps.

Worked example: why pattern repeat matters

12 × 14 ft room, 9 ft (108 in) walls, one door → 52 ft perimeter = 624 in − 36 in = 588 in ÷ 20.5 = 29 strips.

The same room needs 50% more paper with a 27 in repeat. Always check the repeat before you order.

Accent wall example

One 12 ft wide × 8 ft high wall: 144 in ÷ 20.5 = 8 strips. Cut length is 100 in, so 3 strips per 33 ft roll, which means 3 double rolls.

Why not just divide square feet?

The square-foot shortcut (wall area ÷ usable sq ft per roll, often quoted as about 25 sq ft per single roll with no repeat, ~22 with a small repeat and ~18 with a large one) is a quick sanity check. It ignores how many full-height strips you can cut from each roll. For the 12 × 14 ft room with 8 ft walls in the chart, the square-foot shortcut gives about 8 double rolls, but the strip method shows you need 10. Use the strip method to order.

Ordering tips

• Buy all rolls from the same batch (dye lot) number. Colors can vary between batches, per York's guidance.
• Order an extra roll for repairs, especially for discontinued-risk or custom papers.
• Peel-and-stick panels are often sold in different widths and lengths. Redo step 2 with their exact size.
• Removing old paper first? See how to remove wallpaper from a wall. For walls you'll paint instead, use the paint calculator.

Related guides

• How to remove wallpaper from a wall
• Paint calculator
• Drywall sheets calculator: if walls need repair first
• How to fix nail pops in drywall
• Laser measure vs tape measure