How many wallpaper rolls do I need?

Measuring for wallpaper is different from measuring for paint because the rolls have fixed dimensions and you need to account for pattern matching. Here is how to get accurate measurements:

1. Measure the room perimeter: Walk around the room and measure the length of each wall at the floor or ceiling level. Add all measurements together to get the total perimeter. Include any alcoves, bay windows, or recessed areas.
2. Measure the wall height: Measure from the baseboard to the ceiling or from the floor to the ceiling if there is no baseboard. Measure in several spots because floors and ceilings are not always perfectly level. Use the tallest measurement.
3. Calculate total wall area: Multiply the perimeter by the wall height. A 36-foot perimeter with 8-foot ceilings gives 288 square feet of wall area.
4. Subtract large openings: For standard doors and windows, you can subtract about 15 to 20 square feet each. However, many wallpaper experts recommend not subtracting openings because the waste from cutting around them often offsets the savings.
5. Calculate roll coverage: Multiply the roll length by the roll width in feet. A standard roll that is 33 feet long and 20.5 inches wide (1.708 feet) covers 33 x 1.708 = 56.4 square feet.

Always round up your final roll count. It is better to have extra wallpaper than to run out in the middle of a project.

Pattern matching is one of the most important factors in wallpaper estimation. The pattern repeat determines how much waste you generate with each strip:

What is a pattern repeat? The vertical distance before the design repeats itself. It is printed on the wallpaper label. A small repeat might be 2 inches, while a large repeat can be 24 inches or more.

Random or free match: The pattern has no specific alignment requirement. Strips can be hung without matching, which minimizes waste. This is the most material-efficient type of wallpaper.

Straight match: Each strip must align horizontally with the next strip at the same point in the pattern. The waste equals roughly one pattern repeat per strip. For an 8-foot wall with a 24-inch repeat, each strip may need 10 feet of material to ensure the pattern aligns.

Drop match: The pattern on alternating strips is offset by half the repeat length. This creates a diagonal visual effect but requires more careful cutting and generates about the same waste as a straight match.

Use the waste allowance field in the wallpaper calculator to account for pattern matching. For no-match patterns, 5 to 10 percent waste is sufficient. For large pattern repeats (20 inches or more), increase the waste to 20 percent or more.

Different wallpaper types have different installation requirements and durability characteristics:

Vinyl wallpaper: The most common and durable type. Vinyl wallpaper is moisture-resistant and easy to clean, making it ideal for kitchens, bathrooms, and high-traffic areas. It is available in a wide range of colors and patterns.

Non-woven wallpaper: Made from a blend of natural and synthetic fibers. Non-woven wallpaper is breathable, mold-resistant, and easy to install because the paste is applied to the wall rather than the paper. It is also easier to remove than traditional wallpaper.

Paper wallpaper: Traditional wallpaper made from paper. It is less durable than vinyl but offers a classic look and feel. It is best suited for low-traffic areas like bedrooms and dining rooms.

Textile wallpaper: Made from fabric, silk, or natural fibers. Textile wallpaper adds texture and warmth to a room but is more expensive and harder to clean. It requires professional installation in most cases.

Peel-and-stick wallpaper: A modern option with adhesive backing. It is easy to install and remove, making it popular for renters and temporary decor. Peel-and-stick works best on smooth, clean walls.

When using the wallpaper calculator, the type of wallpaper does not directly affect the roll count, but heavier or textured wallpapers may require more waste allowance because they are harder to align perfectly on the first try.

Follow these steps for a professional-looking wallpaper installation:

1. Prepare the walls: Walls must be clean, smooth, and dry. Fill any holes or cracks with spackle and sand smooth. Remove old wallpaper completely. Apply a primer designed for wallpaper to help adhesion and future removal.
2. Mark a plumb line: Use a level or plumb bob to draw a vertical line on the wall as a starting guide. Even in a new house, walls and corners are rarely perfectly straight.
3. Cut strips: Cut each strip to the wall height plus 2 to 4 inches of excess at the top and bottom. For patterned wallpaper, ensure the pattern aligns between strips.
4. Apply paste: For paste-the-paper products, apply paste evenly with a brush or roller and let it soak for the time recommended by the manufacturer. For paste-the-wall products, apply paste directly to the wall.
5. Hang the first strip: Align the strip with your plumb line and smooth it onto the wall using a smoothing brush or wallpaper squeegee. Work from the center outward to remove air bubbles and excess paste.
6. Trim excess: Use a sharp knife and a wide putty knife to trim the excess wallpaper at the ceiling and baseboard. Change blades frequently for clean cuts.
7. Butt seams: Align the next strip edge-to-edge with the previous one without overlapping. For vinyl wallpaper, use a seam roller lightly to ensure adhesion.
8. Clean as you go: Wipe away excess paste with a damp sponge before it dries. Dried paste can be difficult to remove without damaging the wallpaper.

If you are applying wallpaper over existing wallpaper, or planning for future removal, here is what to know:

• Test a corner: Before removing all the wallpaper, test a small section to determine the best removal method. Some wallpaper peels off easily, while others require steaming or chemicals.
• Use a scoring tool: For vinyl wallpaper, score the surface with a paper tiger or scoring tool to allow removal solution to penetrate.
• Apply removal solution: Use hot water mixed with fabric softener or a commercial wallpaper remover. Apply with a spray bottle or sponge and let it soak for 15 to 20 minutes.
• Steam removal: For stubborn wallpaper, a handheld steamer can speed up the process. Be careful not to damage the drywall underneath.
• Prepare for re-wallpapering: After removal, wash the walls to remove adhesive residue and prime them before hanging new wallpaper.

For example, for a 12×10 ft room with 8-ft ceilings, 20.5-in wide rolls at 33 ft long, 15% waste:

1. Wall perimeter = 2 × (12 + 10) = 44 ft
2. Wall area = 44 × 8 = 352 sq ft
3. Roll area = 33 × (20.5 ÷ 12) = 56.38 sq ft
4. Effective roll area = 56.38 × (1 - 0.15) = 47.92 sq ft
5. Rolls needed = 352 ÷ 47.92 = 7.35 → 8 rolls