How to use this calculator
Measure your room's length and width in feet, then enter the wall height (most rooms are 8 feet). Add the number of doors and windows so the calculator can subtract those areas from the total.
If your wallpaper has a pattern repeat, enter the repeat length in inches. This is usually listed on the wallpaper roll or product page. The calculator adds 15% waste to account for pattern matching between strips.
The calculator assumes standard door sizes (3 x 7 feet = 21 sq ft) and standard window sizes (3 x 5 feet = 15 sq ft). If your doors or windows are significantly larger or smaller, adjust the count accordingly.
Single rolls vs double rolls
In the US, wallpaper is traditionally measured in single rolls (roughly 36 square feet of usable coverage) but sold in double rolls (72 square feet). This is an industry quirk that confuses a lot of buyers.
When you see wallpaper priced "per roll," it often means per single roll, but you receive a double roll. Always confirm with the retailer whether their pricing and shipping is per single or double roll before ordering.
European wallpaper rolls are sized differently, typically 10 meters long by 53 cm wide, which works out to about 57 square feet per roll. If you are using European wallpaper, the single roll estimate from this calculator will be conservative.
Frequently asked questions
How many rolls of wallpaper do I need for a 12x12 room?
A 12x12 room with 8 foot ceilings has 384 sq ft of wall area. After subtracting one door and two windows, you have about 333 sq ft. That requires roughly 10 single rolls or 5 double rolls. If your pattern has a repeat, add one extra roll.
What is the difference between single and double rolls?
A single roll covers about 36 usable square feet. A double roll covers about 72 usable square feet. Most wallpaper in the US is sold in double rolls but priced per single roll, so always confirm with your retailer.
What is pattern repeat and why does it matter?
Pattern repeat is the distance before a design repeats on the roll. You must align the pattern between adjacent strips when hanging, which creates waste from trimming. A larger repeat means more waste. This calculator adds 15% for pattern matching.
How do I handle irregular rooms?
For L shaped rooms, calculate each rectangular section separately and add the results together. For rooms with angled walls or dormers, measure the tallest point and treat it as a full wall. Always round up and order an extra roll for safety.