Wallpaper Calculator

1. Enter the room length and width in feet.
2. Set the ceiling height (default 8 ft).
3. Enter the number of doors and windows to subtract.
4. Choose your roll size or pick Custom and enter your own dimensions.
5. If your wallpaper has a pattern, enter the pattern repeat in inches. Use 0 for solid color.
6. Optionally enter the cost per roll for a total estimate.
7. Read the rolls needed, wall areas, and method breakdown.

A wallpaper calculator estimates how many rolls of wallpaper you need to cover the walls of a room. It accounts for the room perimeter, ceiling height, doors and windows, and the roll dimensions you plan to buy.

Wallpaper is sold in rolls of fixed width and length, and you almost always need to round up to whole rolls. If your wallpaper has a repeating pattern, you lose extra material matching that pattern at every strip, which increases the roll count.

Getting the count right saves money. Too few rolls means a mid-project shortage and possible dye-lot mismatch; too many means waste and returns. See the construction calculators hub for more building and home-improvement tools.

The calculator uses two methods depending on whether your wallpaper has a pattern repeat.

Why the Pattern Method Uses More

Each strip must be cut long enough to match the pattern to its neighbor. The extra length per strip is equal to the pattern repeat distance. With a large repeat on a short roll, you may only get two usable strips per roll instead of three or four.

Take a room that is 12 x 10 feet with 8-foot ceilings, 1 door and 2 windows, using US single rolls (27 inches wide, 27 feet long, about 57 sq ft usable).

No Pattern Repeat

Perimeter = 2 x (12 + 10) = 44 ft. Gross area = 44 x 8 = 352 sq ft. Subtract 1 door (21 sq ft) and 2 windows (24 sq ft) = 307 sq ft net. With 10% waste: 307 x 1.10 = 337.7 sq ft. Rolls = ceil(337.7 / 57) = 6 rolls.

With 21-inch Pattern Repeat

Perimeter in inches = 44 x 12 = 528. Strips = ceil(528 / 27) = 20 strips. Each strip needs 8 ft x 12 + 21 = 117 inches. Roll length = 27 x 12 = 324 inches. Strips per roll = floor(324 / 117) = 2. Rolls = ceil(20 / 2) = 10 rolls.

The pattern repeat nearly doubles the roll count in this example.

Wallpaper rolls come in several standard sizes. US rolls are often sold as double rolls even when priced per single.

These are labeled defaults. Always check the actual dimensions printed on your wallpaper packaging because manufacturers vary.

A pattern repeat is the vertical distance between one point in a design and the next identical point. Common repeats range from 6 inches for small geometrics to 24 inches or more for large florals.

Straight Match vs Drop Match

A straight match lines up at the same height on every strip. A drop match (half-drop) shifts down by half the repeat on alternating strips, which can create even more waste. This calculator uses the straight-match method, which is conservative enough to cover most drop matches as well.

Why It Matters

A 21-inch pattern repeat on a standard US roll means each strip uses 117 inches of paper (96 inches of wall height plus 21 inches of matching waste). That cuts the strips per roll from about 3 to just 2, increasing total rolls by roughly 50 percent.

1. Choose a Small or No Pattern Repeat

Solid colors, textures without a directional pattern, and small repeats under 6 inches waste the least paper.

2. Use Wider Rolls

Wider rolls mean fewer seams and fewer edge-trim cuts. A 36-inch wide roll uses fewer strips than a 27-inch roll for the same wall.

3. Measure Twice

Accurate room measurements prevent surprise shortages. Measure each wall individually if the room is not perfectly rectangular.

4. Save Off-cuts

Short pieces left at the end of a roll can often cover the area above doors and windows.

5. Order One Extra Roll

An extra roll from the same dye lot protects you against hanging mistakes and future repairs.

The calculator uses industry-standard opening sizes for quick estimation.

If your doors or windows are significantly larger or smaller, adjust the count accordingly or use the custom approach of measuring net wall area directly.

Room Shape and Layout

Rectangular rooms are straightforward. L-shaped rooms, alcoves and bay windows add perimeter and waste. Measure each wall segment separately for odd layouts.

Ceiling Height

Every extra foot of ceiling height adds one roll width of wall area around the entire perimeter. A 9-foot ceiling needs roughly 12 percent more wallpaper than an 8-foot ceiling.

Pattern Repeat Size

The single biggest waste factor. A 24-inch repeat can nearly double the roll count compared to a solid color on the same room.

Roll Width and Length

Wider and longer rolls yield more usable strips per roll. European rolls are narrower than US rolls, so the same room may need more of them.

Number and Size of Openings

More doors and windows reduce the net wall area. Large picture windows save more wallpaper than small ones.

Planning a Purchase

Run the calculator before you shop to know how many rolls to buy. This prevents mid-project shortages and dye-lot mismatches from reorders.

Comparing Wallpaper Options

Enter different roll sizes and pattern repeats to see how each choice changes the total roll count and cost.

Budgeting a Room Makeover

Enter the cost per roll to get a total material estimate. Pair it with the paint coverage calculator if you are painting trim or an accent wall.

Hiring a Professional

Knowing your own roll estimate helps you evaluate a contractor's quote. If their number differs significantly, ask why.

1. Forgetting the Pattern Repeat

Ignoring the pattern repeat is the most common error. It can increase your roll count by 40 to 60 percent for large patterns.

2. Using Gross Area Without Subtracting Openings

Counting doors and windows as solid wall overestimates rolls, wasting money.

3. Confusing Single and Double Rolls

US wallpaper is priced per single roll but often packaged as double rolls. Make sure you know which unit your store is selling.

4. Not Checking the Dye Lot

Colors can vary between production batches. Buy all your rolls from the same lot, and order one extra rather than risking a mismatch later.

5. Measuring Only One Wall

Rooms are rarely perfectly square. Measure each wall and use the total perimeter for accuracy.

The calculator is exact for the geometry it models but makes simplifying assumptions.

About 6 US single rolls for an 8-foot ceiling with one door and two windows, assuming no pattern repeat. With a 21-inch pattern repeat, expect about 10 rolls.

The vertical distance between one point in the design and the next identical point. It determines how much extra paper you waste matching the pattern from strip to strip.

A US single roll is 27 inches wide and 27 feet long. A double roll is the same width but 54 feet long. Stores often price per single but sell double rolls.

Plan for about 10 percent waste with solid or textureless wallpaper. Patterned wallpaper waste depends on the repeat size but can reach 40 to 60 percent for large patterns.

Yes. The calculator subtracts 21 sq ft per door and 12 sq ft per window. Skipping this overestimates your roll count.

A standard European roll is 20.5 inches (52 cm) wide and about 33 feet (10 meters) long, yielding roughly 52 sq ft of usable coverage.

Measure the length and width of the room in feet, plus the floor-to-ceiling height. Count each standard door and window. For odd-shaped rooms, measure each wall separately and add up the total perimeter.

Experienced hangers reuse off-cuts above openings when the piece is wide enough and the pattern matches. This calculator does not subtract for this, keeping the estimate conservative.

Yes. Always buy at least one extra roll from the same dye lot for repairs, mistakes, and future touch-ups. Matching a dye lot later is difficult.

Yes. Taller ceilings increase the wall area and also reduce the number of usable strips per roll, especially with a pattern repeat.

• Wallpaper roll sizing conventions (This Old House; roll sizing, pattern repeats and hanging method).
• Wallpaper pattern matching guide (Sherwin-Williams; straight and drop match patterns, roll coverage).
• Interior wall measurement standards (Bob Vila; measuring rooms, standard openings and waste factors).