## How Much Wallpaper Do You Need? A Comprehensive Guide to Calculating Your Wallpaper Needs
Planning a wallpaper project can be an exciting way to refresh your living space, but a common stumbling block for DIY enthusiasts and seasoned decorators alike is accurately calculating how much wallpaper to purchase. Running out of wallpaper mid-project is frustrating, while overbuying can lead to unnecessary expense. This guide will walk you through the essential steps to ensure you buy just the right amount, saving you time, money, and potential headaches. We’ll cover everything from precise measurements to understanding pattern repeats and accounting for waste, empowering you to tackle your wallpapering with confidence and achieve a beautifully finished result.
Understanding the basics of wallpaper measurement is crucial for any successful application. Unlike paint, where you can often get away with a little extra, wallpaper comes in fixed-size rolls and requires careful calculation to ensure pattern matching and a seamless finish. The standard double roll, which is the most common size, typically measures around 20.5 inches wide and 33 feet long. However, roll sizes can vary by manufacturer and country, so it’s always best to check the specific dimensions of the wallpaper you intend to use. This seemingly small detail can significantly impact your final quantity.
### Measuring Your Walls Accurately
The first and most critical step in determining how much wallpaper you need is to accurately measure the dimensions of the walls you plan to cover.
* **Height:** Measure the height of each wall from the ceiling to the baseboard or molding. Record this measurement.
* **Width:** Measure the width of each wall. If a wall has multiple sections separated by doors or windows, measure each section individually.
* **Obstructions:** Note the width and height of any doors, windows, or other significant architectural features. While you’ll need to cut around these, they help in calculating the total wall area.
It’s recommended to measure in inches for maximum precision, as wallpaper is typically measured and sold in inches.
### Calculating Total Square Footage
Once you have your measurements, you can calculate the total square footage of your walls.
1. **Calculate the area of each wall:** Multiply the height of each wall by its width.
2. **Sum the areas of all walls:** Add together the areas of all the walls you intend to wallpaper.
3. **Subtract areas of openings:** For each door and window, calculate its area (width x height) and subtract these from the total wall area.
4. **Convert to square feet:** If you measured in inches, divide the total square footage by 144 (since there are 144 square inches in a square foot).
This will give you a baseline area to start with. However, this number alone isn’t sufficient due to pattern repeat and waste.
## Understanding Pattern Repeat and Its Impact
The “pattern repeat” is the distance along the length of the wallpaper roll where a design repeats itself. This is a critical factor in calculating how much wallpaper you need, as it dictates how you’ll need to cut and align strips of wallpaper to ensure a continuous and aesthetically pleasing pattern across your walls. A larger pattern repeat means more wallpaper will be used for each strip, as you’ll need to discard more material to match the design.
### Types of Pattern Repeats
There are generally three types of pattern repeats to be aware of:
* **Straight Match:** The pattern on one strip aligns directly with the pattern on the next strip. This is the most common and easiest to work with.
* **Half-Drop Match:** The pattern on one strip is centered on the next strip, meaning the design drops by half its vertical repeat. This requires more wallpaper and careful alignment.
* **Random Match:** The pattern doesn’t need to be matched between strips. This is less common and usually found in textured or very small, all-over patterns.
The manufacturer’s instructions will always specify the type of match and the pattern repeat measurement.
A common misconception is that you can simply divide your total wall area by the square footage of a wallpaper roll. This approach often leads to underestimation, especially with patterned wallpapers that have a significant repeat. Always factor in the pattern repeat when calculating your needs.
## Calculating Rolls Needed: Accounting for Waste and Pattern Repeat
After calculating your wall area, you need to factor in pattern repeat and an allowance for waste. Waste can occur due to cutting errors, trimming edges, and, most significantly, aligning patterns. A general rule of thumb is to add 15-20% to your total square footage to account for these factors.
1. **Determine the number of strips per roll:** Divide the length of your wall (in inches) by the width of the wallpaper roll (in inches). This tells you how many horizontal strips you can get from a single roll.
2. **Account for pattern repeat:** If you have a pattern repeat, you must add the repeat measurement to the height of each strip you cut. For example, if your wall is 8 feet (96 inches) high and your pattern repeat is 18 inches, each strip you cut needs to be 96 + 18 = 114 inches long.
3. **Calculate strips per roll with repeat:** With the adjusted strip length (including the pattern repeat), determine how many strips you can get from a single roll. Divide the total length of the roll (e.g., 33 feet or 396 inches) by your adjusted strip length.
4. **Calculate total strips needed:** Divide the total width of your walls (in inches) by the width of the wallpaper roll (in inches). This gives you the total number of vertical strips required.
5. **Calculate total rolls:** Divide the total number of strips needed by the number of strips you can get per roll. Round up to the nearest whole number.
A more straightforward method often recommended by wallpaper manufacturers is to:
* Measure the perimeter of the room in feet.
* Divide the perimeter by the width of the wallpaper roll in feet (usually around 1.7 feet for a 20.5-inch roll). This gives you the number of strips needed.
* Measure the height of your walls in feet.
* Add the pattern repeat (in feet) to the wall height.
* Divide the total roll length (in feet) by this adjusted wall height to find out how many strips you get per roll.
* Divide the total number of strips needed by the number of strips per roll. Round up.
Dealing with Doors and Windows
While you subtract the area of doors and windows from your total wall area calculation, you still need to account for the wallpaper needed to cover the wall space around them. For these areas, measure the height from the top of the window/door to the ceiling, and the width of the wall on either side of the opening. You will use full strips for these sections, and the pattern repeat will still apply.
It’s always better to have a little extra wallpaper than not enough. The extra rolls can be used for future repairs or for smaller accent projects. Unopened rolls can often be returned to the retailer, but check their return policy beforehand.
Additional Tips for Accurate Wallpaper Calculation
Beyond the basic measurements and pattern repeat considerations, several other factors can influence the amount of wallpaper you need.
* **Ceiling Height Variations:** If your room has varying ceiling heights, measure each section separately to ensure accuracy.
* **Busyness of the Pattern:** Intricate or busy patterns can be more forgiving with slight mismatches than simple, bold designs.
* **Quality of Wallpaper:** Higher quality wallpapers often have more robust backing and are more forgiving during application.
* **Experience Level:** If you are a beginner, it’s wise to add an extra 10-15% to your calculated amount to account for potential mistakes or learning curve challenges.
### When to Buy an Extra Roll
It is almost always recommended to purchase at least one extra roll of wallpaper, especially for larger projects or when using a discontinued pattern. This extra roll acts as a safety net for any unforeseen issues, such as accidental damage during application, or for future repairs. If the pattern is discontinued, finding a matching roll later can be impossible.
### Considering Wallpaper Kits or Murals
For specific design choices like wallpaper murals or large-scale scenic wallpapers, the calculation process can differ. These are often sold in pre-cut panels or as a complete kit, and the manufacturer’s instructions will guide you on how to measure your wall and order the correct size.
## Frequently Asked Questions (FAQ)
### Q1: How do I account for a large pattern repeat?
A large pattern repeat will require more wallpaper. You must add the repeat measurement to the height of each strip you cut to ensure the pattern matches seamlessly from one strip to the next. This will reduce the number of usable strips you can get from a single roll.
### Q2: Can I use wallpaper left over from a previous project?
Only if the leftover wallpaper is from the exact same dye lot and pattern. Slight variations in color or pattern can occur between different batches, making it impossible to achieve a seamless look if mixed.
### Q3: What is a “dye lot”?
A dye lot is a batch number from the manufacturer that indicates a specific printing run. Wallpaper from the same dye lot will have consistent color and pattern. It’s crucial to ensure all rolls you purchase for a project come from the same dye lot and to check this information on the wallpaper label.
### Q4: How much wallpaper should I buy for a small powder room?
For a small room, still follow the same measurement principles. Measure the
