How to Calculate Wallpaper for Any Room
Wallpaper math trips up a lot of people because of pattern repeats. Here's how to get it right the first time.
Measure Wall Area First
Measure the width and height of each wall you're papering. Multiply width by height to get wall area in square feet. Add all walls together for total area.
Subtract half the area of doors and windows — most installers keep the math simple by subtracting only large openings (wider than 36 inches). Small windows are often ignored in the estimate because you lose that material to pattern matching anyway.
A standard single roll of wallpaper covers 25 to 27 square feet. Double rolls (also called bolts) cover 57 square feet. Most wallpaper is sold in double rolls even when priced per single roll — check the label.
Pattern Repeat: The Number Everyone Forgets
Pattern repeat is the vertical distance before the pattern repeats itself. A 24-inch repeat means every strip must be cut to start at the same point in the pattern, wasting up to 23 inches per strip.
Small or no repeat (0 to 6 inches): add 10% waste. Medium repeat (6 to 18 inches): add 20%. Large repeat (18 to 36 inches): add 30% or more.
Straight match patterns (where the repeat lines up horizontally across strips) waste less than drop match patterns (where every other strip is offset by half a repeat). Check your wallpaper label for match type.
Free tool: Wallpaper Calculator →
Calculate Strips and Rolls
Divide wall width by wallpaper width (usually 20.5 or 27 inches) and round up to get the number of strips per wall. Multiply by the number of walls.
Divide ceiling height by wallpaper length per strip (ceiling height plus one repeat) to get usable cuts per roll. Divide total strips by cuts per roll to get roll count.
Our wallpaper calculator handles all of this — enter room dimensions, ceiling height, and pattern repeat and it tells you exactly how many rolls to order.
Waste and Safety Stock
Always order at least one extra roll beyond your calculated need. Wallpaper is dye-lot sensitive — rolls from a different production run can have subtle color differences. Having extra from the same lot protects you.
If you're papering an accent wall only, the formula is simpler: measure width and height, divide by roll coverage, add one roll.
Keep any leftover rolls. They're invaluable for future repairs — a torn seam or damaged section can be patched invisibly with matching paper from the same lot.
Wallpaper Cost Estimates
Wallpaper ranges from $1 to $10 per square foot for material, depending on type. Vinyl is the most affordable and most durable. Natural fiber wallpapers (grasscloth, silk) are at the high end.
Professional installation adds $1 to $3 per square foot. A standard 12×14-foot room with 9-foot ceilings costs $300 to $900 total installed — materials plus labor.
Prep work matters. Wallpaper applied to unpainted drywall or improperly primed surfaces will not hang cleanly and may tear when removed. Prime walls with wallpaper primer before hanging.
Related free calculators
Stop estimating by hand
ProBuildCalc scans a room with your iPhone's LiDAR and builds the square footage, material takeoff, and a blueprint automatically.
FAQ
- How many square feet does a roll of wallpaper cover?
- A standard single roll covers 25–27 square feet. Most wallpaper is sold in double rolls (bolts) covering about 57 square feet. Always check the label — coverage varies by brand.
- How do I account for pattern repeat when calculating wallpaper?
- Add 10% extra for patterns with a small repeat (under 6 inches), 20% for medium repeats (6–18 inches), and 25–30% for large repeats over 18 inches.
- Should I subtract windows and doors from my wallpaper calculation?
- Only subtract large openings wider than 36 inches. Small windows are usually ignored because you lose that material to pattern matching cuts anyway.
- What happens if I run out of wallpaper mid-project?
- You risk a dye-lot mismatch — rolls from a different production run may look slightly different. Always order one extra roll from the same lot as insurance.