Measure the width and height of each wall you plan to cover. Use a metal tape measure for accuracy. For height, measure from the baseboard to the ceiling or crown molding. If you have intricate details like arched windows or built-in shelving, measure the total width and height of the wall first, then subtract the areas you won’t be covering.
For a standard rectangular room, measure the length of each of the four walls. Add these lengths together to get the total perimeter of the room. Multiply this total perimeter by the height of the walls you measured earlier. This gives you the gross square footage of the walls.
For example, if your room is 10 feet wide and 12 feet long, and the walls are 8 feet high: The perimeter is (10 + 12 + 10 + 12) = 44 feet. The gross wall area is 44 feet * 8 feet = 352 square feet.
Subtracting windows and doors
Now, you need to account for areas you won’t be wallpapering, primarily windows and doors. Measure the width and height of each window and door. Multiply the width by the height for each to get its square footage. For a standard door (typically 30 inches wide by 80 inches high), this is 2.5 feet * 6.67 feet = 16.7 square feet. For a standard window (e.g., 36 inches wide by 48 inches high), this is 3 feet * 4 feet = 12 square feet.
Sum the square footage of all windows and doors. Subtract this total from the gross wall area calculated earlier. If your room has two doors totaling 33.4 sq ft and three windows totaling 36 sq ft, that’s 69.4 sq ft to subtract. So, 352 sq ft (gross area) – 69.4 sq ft (doors/windows) = 282.6 square feet of net wall area.
Be conservative. If a window is unusually shaped or you’re unsure about exact dimensions, it’s better to overestimate slightly than underestimate. For very large windows or multiple openings, it can be worth sketching out the wall and marking dimensions.
Accounting for waste and pattern repeat
Wallpaper isn’t sold in exact square footage. It comes in rolls with specific dimensions. You’ll need to factor in waste due to pattern matching and cutting. The amount of waste depends heavily on the wallpaper’s pattern repeat – the vertical distance before the pattern starts to repeat.
A larger pattern repeat means you’ll have more waste because you need to align larger sections of the pattern. For wallpapers with a large pattern repeat (e.g., 20 inches or more), you might need to add 20-30% to your net wall area to account for waste. For smaller, more forgiving patterns, 10-15% might suffice. Always check the manufacturer’s recommendations for waste percentage, as it can vary significantly.
This is why using a dedicated wallpaper roll calculator is essential. It takes your net wall area and the specific roll dimensions and pattern repeat of the wallpaper you choose to determine the exact number of rolls needed. Simply calculating square footage isn’t enough; you must translate that into rolls.
Understanding wallpaper roll dimensions
Standard US wallpaper rolls typically measure 20.5 inches wide by 33 feet long. This yields approximately 56.4 square feet per roll. However, ‘double rolls’ are common and are twice the length, often measuring 20.5 inches wide by 66 feet long, providing about 112.8 square feet per roll. Always verify the dimensions of the specific wallpaper you are purchasing.
Some European wallpapers might come in different widths, such as 21 inches or 27 inches. This is where precise measurement and calculation become even more critical. A wider roll can sometimes mean fewer seams but also potentially more waste if the pattern repeat is large.
How different room shapes affect calculations
Calculating for a simple rectangular room is straightforward. However, rooms with alcoves, bay windows, or angled walls require more detailed measurements. For an alcove, treat each surface within the alcove as a separate wall and measure its height and width individually. Add these areas to your total.
Bay windows often consist of multiple angled walls. Measure each segment of the bay window separately, including the height and width of each section. If there are windows within the bay, subtract their areas as usual. The key is to break down complex shapes into simpler rectangular or triangular components that you can measure.
Ceiling height variations also play a role. If your ceiling height isn’t uniform, use the highest measurement for your calculations, or average the heights for different sections if the variation is significant and consistent.
Calculating for specific architectural features
Features like fireplaces, built-in bookshelves, or wainscoting need careful consideration. If you are wallpapering around a fireplace that extends from floor to ceiling, measure its width and height and subtract that area. If the fireplace is recessed, you might only need to wallpaper the sides and back, so measure those surfaces individually.
For built-in bookshelves, you’ll typically only be wallpapering the back panel and potentially the sides. Measure these specific areas. Avoid including the shelf surfaces themselves unless you intend to wallpaper them (which is uncommon).
Wainscoting is usually installed at a lower portion of the wall, typically 30-36 inches from the floor. You would measure the height from the top of the wainscoting to the ceiling and calculate the square footage for that upper section only. Measure the perimeter of the room and multiply by the height of the wallpapered section.
When to use a wallpaper square footage calculator
A wallpaper square footage calculator is a tool that helps you estimate the total surface area of your walls in square feet. While useful for an initial estimate, it’s crucial to understand that this number alone doesn’t tell you how many rolls of wallpaper to buy. That’s where a how much wallpaper do I need calculator comes in, as it incorporates roll dimensions and pattern repeat.
Use the square footage calculation to get a ballpark figure. This helps you budget and compare different wallpaper options. For instance, if you’re looking at two different patterns, you can compare the total square footage required for each, assuming similar pattern repeats and roll sizes.
However, for precise ordering, you must convert your calculated net wall area into the number of wallpaper rolls. This conversion is highly dependent on the specific wallpaper’s roll size and its pattern repeat. Always refer to the wallpaper manufacturer’s specifications for these details. Ordering precisely the calculated square footage without accounting for pattern matching and cut-offs is a common mistake that leads to insufficient wallpaper.
Common mistakes to avoid
Ordering too little wallpaper is the most frequent and costly error. This often happens when people only calculate gross wall area and don’t subtract windows/doors, or when they neglect pattern repeat and waste. If you run out of wallpaper and the pattern is discontinued or from a different dye lot, finding an exact match can be impossible, leading to visible seams or the need to re-wallpaper the entire room.
Another mistake is not measuring accurately. Using a flexible tape measure or estimating distances can lead to significant errors. Always use a sturdy metal tape measure. Measure twice, cut once applies here; measure your walls twice before ordering.
Not accounting for ceiling height variations or complex architectural features can also lead to underestimation. Be meticulous with your measurements in detailed areas.
Finally, assuming all rolls are the same size is a mistake. European rolls, US standard rolls, and double rolls have different coverage. Always check the dimensions and calculate based on the specific product you choose. For cost-effectiveness and accurate ordering, a tool like the wallpaper roll calculator is indispensable.
Tips for accurate wallpaper measurement
Always start with a clean, clear wall. Remove any old wallpaper, nails, or debris. Ensure baseboards and trim are intact. If baseboards are being replaced, measure the wall height *after* new baseboards are installed.
When measuring height, start from the floor or the top of the baseboard and go straight up to the ceiling or crown molding. If you have coved ceilings, measure to the highest point of the cove.
For width, measure along the baseboard from corner to corner. Ensure your tape measure is held taut and level. If you have an unusually long wall, break it down into smaller, measurable sections.
Mark your measurements lightly with a pencil on the wall or on a piece of paper. Keep a running tally of each wall’s dimensions and the total perimeter. Note down the dimensions of all windows, doors, and other openings. This detailed record will be invaluable when using a calculator or when ordering.
Calculating for different types of wallpaper
While the basic measurement process remains the same, certain wallpaper types might influence your waste calculations. For instance, textured wallpapers or those with metallic finishes might have specific recommendations from the manufacturer regarding pattern matching. Vinyl wallpapers are generally durable and easier to clean but can be thicker, potentially affecting how much pattern needs to be matched perfectly.
Grasscloth and natural fiber wallpapers often have less of a defined pattern repeat but can be more delicate and may require extra care during installation, potentially leading to slightly more waste. Digital or custom-print wallpapers might have very large or unique pattern repeats, so always check the specifications.
No matter the material—be it traditional paper, vinyl, or a specialty type like Rifle Paper Co. wallpaper or floral wallpapers—the principle of measuring your wall area accurately and then translating that into rolls with sufficient overlap for pattern matching and waste is constant.
Finalizing your wallpaper order
Once you have your net wall area and have factored in the waste percentage based on the wallpaper’s pattern repeat and manufacturer’s guidelines, you can determine the total square footage you need to purchase. Then, use the dimensions of the specific wallpaper roll (width and length) to calculate how many rolls that equates to. Many online wallpaper roll calculators perform this conversion for you automatically.
It’s always prudent to order at least one extra roll, especially for larger projects or if you anticipate needing to patch the wall in the future. Having an extra roll from the same dye lot ensures a perfect match if repairs are ever needed. This small extra cost can save a significant headache down the line.
Remember that the cost of wallpaper is often calculated per roll, not per square foot. Therefore, understanding how many square feet each roll covers, and how much total square footage you need, is the most direct path to accurately budgeting and ordering your wallpaper. The installation cost itself is a separate consideration, often based on labor hours or a per-roll fee, which you can explore with a Wallpaper Installation Cost Calculator.
By meticulously calculating your wallpaper square footage, you ensure you buy enough material, avoid costly mistakes, and set yourself up for a successful and beautiful wallpaper installation.