Should doors and windows be deducted?

Yes, deduct full-size doors and windows. Very small openings are often left in as a natural buffer, because pattern matching creates waste anyway.

What is pattern repeat?

Pattern repeat is the vertical distance before the design starts again. Each strip has to be cut at a whole number of repeats so the pattern lines up, which increases the amount of paper you need.

What is the difference between a single roll and a double roll?

Wallpaper is often priced per single roll but packaged as a double roll (two singles in one continuous bolt). A double roll usually yields more usable full-height strips, so always confirm the packaged length before ordering.

How much extra wallpaper should I buy?

Most installers add 10% to 20%. Plain or non-repeating papers sit near 10%; large drop-match patterns, angled walls, and stairwells sit closer to 20%.

Why should wallpaper rolls come from the same dye lot?

Wallpaper is printed in batches. Two rolls of the same pattern from different dye lots can differ slightly in color, and the seam between them can be visible on the wall.

Paint, Flooring and Wall Projects

About 6 min

Wallpaper Quantity Estimator

Enter your walls, deduct doors and windows, add your wallpaper roll dimensions and pattern repeat, then choose a waste allowance. The estimator returns net wallpaper area, the number of full-height strips required, strips per roll, and an estimated roll count rounded up to whole rolls.

How this tool works

Total wall area is calculated from each wall's width and height, openings are deducted, and the usable strip length is rounded up to a whole pattern repeat. The number of strips needed per wall is the wall width divided by the roll width, rounded up. Strips available per roll is the roll length divided by the strip length, rounded down. Rolls are then rounded up after the waste allowance.

Example: A 12 ft × 9 ft wall with one door, 20.5 in wide rolls that are 33 ft long, and an 18 in straight repeat needs 8 strips of 108 in each. Each roll yields 3 strips, so about 3 rolls before waste and 4 rolls with a 15% allowance.

Assumptions used

Walls are treated as rectangles (width × height).
A standard door is counted as 21 sq ft (3 ft × 7 ft) and a standard window as 15 sq ft (3 ft × 5 ft). Custom openings use your own measurements.
Strip length is rounded up to a whole pattern repeat for a straight match, plus half a repeat for a drop match.
Strips per roll uses the tallest wall entered, which is the conservative approach.
Roll count is always rounded up to a whole roll after the waste allowance is applied.

Practical tips

Buy every roll from the same dye lot where possible — color can shift noticeably between lots.
Keep one spare roll for repairs; matching later is often impossible.
Confirm whether the retailer sells single rolls, double rolls, or bolts before ordering.
Large pattern repeats increase waste. Ask for the manufacturer's stated coverage for your specific pattern.

Frequently asked questions

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Keep planning

Paint Quantity EstimatorEstimate how much paint may be needed based on wall measurements, openings, coats, and paint coverage.Flooring Square Footage EstimatorCalculate flooring square footage, waste allowance, and estimated box quantity for one or multiple rooms.Tile Quantity EstimatorEstimate tile quantity, square footage, waste allowance, and box count for floors, backsplashes, shower walls, and feature walls.

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This estimate is for planning purposes. Wallpaper coverage, roll labeling, pattern matching, wall conditions, and installer methods vary. Confirm product specifications before ordering. Nothing you enter here is stored by Total Home Fusion.