Wallpaper Calculator
Estimate how many rolls of wallpaper you need for any room — accounting for doors, windows, roll coverage and pattern waste.
Results
Buy from the same dye lot and keep one extra roll — wallpaper batches vary noticeably.
How to Use This Wallpaper Calculator
- Measure the room length, width and wall height in feet.
- Count the doors and windows to subtract their area.
- Enter the usable square footage per roll (25–28 is typical after trimming).
- Add pattern waste — 10% for small repeats, 15–20% for large ones.
The calculator totals the four walls, subtracts openings, adds pattern waste and divides by usable coverage per roll.
Roll Coverage: Single vs. Double Rolls
A standard wallpaper single roll contains roughly 30 square feet of paper. After trimming edges, cutting around openings and matching patterns, the usable area drops to about 25–28 square feet. Many brands sell "double rolls" — one long roll with twice the length — so a package marked "double roll" covers about 56–60 square feet. Check the label for the square footage, and enter the usable per single-roll number into the calculator for an accurate count.
Pattern Matching Waste
- No pattern / solid: 5–10% waste is enough.
- Small repeat (under 12 in): 10–15%.
- Large repeat (12 in+), stripes, or damask: 15–20% or more.
With a large pattern, each strip has to be shifted to line up with the previous one, and the offcut is usually too short for anything else — that waste is unavoidable and should be planned for.
Frequently Asked Questions
How many rolls of wallpaper do I need for a 12x12 room?
A 12×12 room with 8-foot ceilings has about 348 square feet of wall area after subtracting a standard door and window. With 10% pattern waste and 28 usable square feet per roll, that is 14 rolls.
How many square feet does a roll of wallpaper cover?
A standard single roll contains about 30 square feet, but trimming and matching a pattern leaves roughly 25–28 usable square feet. Double rolls contain twice as much.
What is the difference between a single and double wallpaper roll?
A double roll is one long roll with twice the length of a single roll. Most wallpaper is priced and packaged as double rolls even though labels may list square footage per single roll.
How much extra wallpaper should I buy for pattern matching?
Add 10–15% for small repeat patterns and 15–20% for large repeats or vertical stripes. Matching the pattern at each seam creates unavoidable waste.