Wallpaper Calculator
Rolls needed, strips per roll, and pattern-repeat waste — with the strip layout drawn on your wall.
Your estimate
You'll need 3 rolls and 8 strips — about $144.
3 usable strips per roll · each strip cut to 8' 4" · 96 sq ft of wall
Measurements
Roll details
Standard US roll ≈ 20.5 in
0 for a random-match or plain paper
Subtract doors and windows
No openings yet. Add each door or window and its area comes out of the total.
Waste & cost
10% is standard
Each vertical strip drawn at your roll width, so you can see where seams land before you hang the first piece.
The breakdown
- Rolls to buy
- 3
- Strips needed
- 8
- Strip cut length
- 8' 4"
- Usable strips per roll
- 3
- Wall area
- 96 sq ft
- Openings subtracted
- −0 sq ft
- Net area to cover
- 96 sq ft
- Waste overage (10%)
- 1 extra strips
- Pattern repeat
- none
- Coverage bought
- 169.1 sq ft
- Estimated cost
- $144
Where to buy
Hand-picked search links for the materials on your list. As an Amazon Associate, ProjectMath earns from qualifying purchases.
Prices and availability are set by the retailer and change often. Always confirm the exact product size matches what this calculator assumed.
How this is calculated
Wallpaper is bought by the roll but hung by the strip, so the honest calculation counts strips first. Pattern repeat is the hidden cost: every strip has to be cut to a whole number of repeats.
- strips needed = ceil(wall width ÷ roll width)
- cut length = wall height rounded up to the next full pattern repeat
- strips per roll = floor(roll length ÷ cut length)
- rolls = ceil(strips needed ÷ strips per roll)
A large repeat can cut usable strips per roll from three to two, which is a 50% jump in rolls for the same wall.
- 1Measure the surfaceMeasure the width and height (or length) of the area in feet, inches, or meters and enter them in the calculator.
- 2Subtract openingsAdd each door, window, or fixture by size and count so their area is removed from the total.
- 3Enter the roll dimensionsUse the roll width and roll length printed on your wallpaper, plus the pattern repeat if the design must line up.
- 4Add a waste overageKeep the default 10% waste allowance for cuts and mistakes, or adjust it for complex layouts and diagonal patterns.
- 5Read the shopping listThe calculator rounds up to whole units to buy and multiplies by your price per unit for an estimated total. Copy or print the plan and take it to the store.
Common questions
How many rolls of wallpaper do I need?
Divide the wall height plus pattern repeat into the roll length to get usable strips per roll, then divide the wall width by the roll width to get total strips needed. This calculator does both and rounds up.
Does pattern repeat change how much I need?
Significantly. A large repeat forces you to waste part of each strip to line the pattern up, which can add a whole roll or more on a big wall.
Should I subtract windows and doors?
Subtract large openings, but never plan to piece a strip around a small window. This calculator removes opening area from the total while still counting full-height strips.
Should I buy extra wallpaper?
Always buy one extra roll from the same batch. Dye lots vary between print runs and a repair later is nearly impossible to match.