Wallpaper Calculator: How to Measure for Wallpaper

To calculate how much wallpaper you need, measure the width and height of your wall in inches or centimetres. Multiply these two numbers to get the total surface area. For standard wallpaper rolls, you then divide this area by the usable square footage of a single roll, always rounding up to the nearest whole roll.

How do I calculate how much wallpaper I need?

The basic calculation for wallpaper is straightforward, but accuracy is everything. Start by determining the total surface area of the wall or walls you plan to cover. You will then use this figure to determine how many rolls of traditional wallpaper you need, or to order a custom-sized wall mural.

The fundamental formula is: Wall Width x Wall Height = Total Area.

For example, let's say you have a single feature wall that is 144 inches wide (366 cm) and 96 inches high (244 cm). The calculation would be:

• In inches: 144 in x 96 in = 13,824 square inches.
• In centimetres: 366 cm x 244 cm = 89,304 square centimetres.

Once you have the total area, the next step depends on the type of wallpaper you are buying. If you are purchasing standard rolls, you need to know the coverage area of one roll. A standard US roll often covers about 28 square feet, while a UK or Euro roll might cover 56 square feet. You would divide your wall's area by the roll's coverage. For our example wall (13,824 sq in = 96 sq ft), you would need four standard US rolls (96 / 28 = 3.4, rounded up to 4). However, this simple calculation does not account for pattern repeat, which we will cover later. This is the single biggest variable that leads to ordering too little or too much wallpaper.

For a made-to-measure product, the process is much simpler. You provide the exact wall dimensions, and the mural is printed to fit. This is the core of how ordering a made to measure mural works at Casavono. You enter your 144-inch width and 96-inch height, and we produce the mural specifically for that space, delivered in numbered panels for easy installation.

What tools do I need to measure for wallpaper?

Gathering the right tools before you start measuring will ensure your figures are precise, saving you time and money. You do not need many tools, but each one plays a critical role in getting an accurate reading. An error of even half an inch can affect the final result, especially on a large wall.

Here is a list of essential measuring tools:

• Metal Tape Measure: A locking metal tape measure is non-negotiable. Fabric or plastic tapes can stretch over time, leading to inaccuracies. A metal tape provides a rigid, straight line for precise measurements.
• Pencil and Paper: A simple but vital part of the process. Write down your measurements immediately. It is easy to forget a number or transpose digits if you try to remember them. Sketching a quick diagram of the room and labelling each wall with its dimensions is also a helpful practice.
• Spirit Level: While not strictly for measuring dimensions, a spirit level is useful for checking if your walls, floors, and ceilings are perfectly horizontal and vertical. Significant slopes can affect your final measurements, as the tallest and widest points may not be at the corners.
• Calculator: For calculating the total area and determining the number of rolls needed, a calculator prevents simple arithmetic errors. You can use a physical calculator or the one on your phone.

Once you have your measurements, you can begin planning your project. Knowing the exact dimensions is the first step in creating a beautiful new space, whether you choose a bold design like the Black Peony Floral Mural or something more serene for a bedroom. For a full list of what you will need for the next stage, see our complete wallpaper installation guide.

Murals made to your measure

Blue Crane Animal MuralPrinted to your wall sizeSage Forest Botanical MuralPrinted to your wall sizeBlack Peony Floral MuralPrinted to your wall size

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How to measure a wall for wallpaper: A step-by-step guide

Measuring a wall accurately is the foundation of a successful wallpaper project. Follow these steps methodically to ensure you get it right. Always measure twice to confirm your numbers before placing an order.

1. Clear the Wall

   Remove any furniture, artwork, or obstructions from the wall. This gives you clear access to measure from corner to corner and floor to ceiling without anything getting in the way.

2. Measure the Width

   Measure the horizontal width of the wall from one corner to the other. To ensure you account for any imperfections, take this measurement at three different points: the top, the middle, and the bottom of the wall. Use the largest of the three measurements as your final width. Walls are rarely perfectly square, so this step captures the widest point.

3. Measure the Height

   Measure the vertical height of the wall from the ceiling to the top of the skirting board (baseboard). Similar to the width, take this measurement at three different points: the left side, the centre, and the right side. Use the largest of these three measurements as your final height. This ensures your wallpaper will cover the entire surface, even if the ceiling or floor is slightly uneven.

4. Add a Bleed or Contingency

   For any wallpaper project, it is crucial to add a little extra to your final dimensions. For Casavono made-to-measure murals, we recommend adding about 4 inches (10 cm) to both the final width and height. This extra material, known as a bleed, provides a margin for error and accounts for slight variations in wall straightness. The excess is simply trimmed away after installation for a perfect finish. This is a crucial part of how to hang a wall mural correctly.

How does a wallpaper calculator with repeat work?

A wallpaper calculator with repeat is a tool designed to account for the waste generated when matching patterns on traditional wallpaper rolls. Pattern repeat is the vertical distance between the start of one pattern element and the start of the next identical element on the wallpaper. This can range from less than an inch to over 30 inches (76 cm).

When you hang wallpaper with a pattern, each new strip must be aligned with the previous one so the design flows correctly across the wall. This almost always requires you to cut off and discard a portion of the roll at the top of each strip to get the pattern to match. The larger the pattern repeat, the more potential waste you will have. A quiet botanical such as the Sage Forest Botanical Mural might have a large, flowing design that would be difficult to align with standard rolls.

A good wallpaper calculator with repeat functionality will ask for three things: wall height, wall width, and the pattern repeat measurement (found on the wallpaper label). It uses this information to calculate how many full vertical drops you can get from a single roll and how many rolls you will need to complete the wall. This is far more accurate than a simple area calculation. However, it still results in buying significant extra material that will be discarded. This is one of the main reasons customers explore made-to-measure options, which eliminate pattern repeat calculations and waste entirely. The entire mural is printed as one continuous image, and the panels are numbered to be hung in sequence without any complex matching.

How much extra wallpaper should I order?

The amount of extra wallpaper you should order depends entirely on whether you are buying standard rolls or a made-to-measure mural. The rules for each are very different, and understanding them is key to avoiding both waste and shortages.

For traditional wallpaper sold in rolls, the industry standard recommendation is to order 10% to 15% more than your calculated need. This extra amount serves as a contingency to cover two main areas. The first is pattern repeat waste, as discussed earlier. The larger and more complex the pattern, the more waste you will generate while aligning strips. The second is for mistakes. If you mis-cut a strip or it gets damaged during installation, having an extra roll on hand is essential. It is always better to have a bit left over than to run out before the job is finished.

For a made-to-measure mural from Casavono, the concept of ordering 'extra' is different and much more efficient. Instead of a percentage, we advise customers to add a small, fixed amount to their precise wall measurements. Our recommendation is to add about 4 inches (10 cm) to the total width and the total height of your wall. This isn't for pattern matching, as our murals are printed as a single image. This small 'bleed' is a safety margin to account for walls that may not be perfectly square. The excess is trimmed off after hanging, ensuring a perfect edge-to-edge fit. This method dramatically reduces waste compared to the 15% overage required for rolls, making it a more sustainable choice.

Should I use an online wallpaper calculator?

Using an online wallpaper calculator is an excellent idea and a great starting point for planning your project. These tools can quickly demystify the process of figuring out material needs. However, it is important to understand that not all online calculators are the same, and you should choose one that matches the product you intend to buy.

Many generic calculators or those found on home improvement store websites are designed for standard, repeating-pattern wallpaper rolls. They will typically ask for your wall dimensions and the specifications of the roll, such as its length, width, and pattern repeat. These are very useful for getting a baseline estimate for a traditional wallpapering job. They help translate your wall area into a specific number of rolls, which is the most confusing part for many people.

In contrast, a brand-specific tool like the Casavono free online wallpaper calculator is designed for a made-to-measure product. This type of calculator is much simpler because it does not need to account for roll coverage or pattern repeat waste. You simply enter your wall's height and width, and the calculator confirms the total area and provides the details for your custom-printed mural. It is a direct calculation of your specific needs, not an estimation based on pre-sized rolls. Using the right calculator for the right product is essential for accurate planning and budgeting.

How do you calculate wallpaper around windows and doors?

A common point of confusion when measuring for wallpaper is how to handle walls with features like windows, doors, or built-in fireplaces. The correct and safest method is to ignore them in your initial measurements. You should measure the wall as if it were a solid, flat rectangle.

Measure the full width of the wall at its widest point and the full height at its tallest point. Do not subtract the area of the window or door. There are two critical reasons for this. First, it ensures you have enough wallpaper to cover the areas above, below, and to the sides of the opening. If you subtract the window, you might end up with several small, unusable offcuts instead of a single piece that can be trimmed to fit.

Second, and most importantly, it guarantees that the pattern of the wallpaper continues uninterrupted across the wall. Imagine a large, scenic design like the White Mountain Landscape Mural. If you were to cut out the window's area from your order, the pattern would be broken. By ordering for the full wall size, you hang the wallpaper panel over the window or door opening and then carefully trim away the excess with a sharp utility knife. This technique maintains the visual flow of the design, making the window or door look like a natural part of the scene rather than an awkward interruption. This is standard professional practice and a key step in how to prepare a wall for wallpaper installation.

What is the difference between a wallpaper roll calculator and a mural calculator?

While both tools aim to help you buy the right amount of wall covering, a wallpaper roll calculator and a mural calculator work on fundamentally different principles because the products themselves are different. Understanding this distinction is key to a successful project. A mural calculator is essentially a direct ordering tool, whereas a roll calculator is an estimation tool that requires you to interpret the results.

A traditional wallpaper roll calculator is designed to solve a puzzle: how many fixed-size units (rolls) are needed to cover a variable-size space, while also accounting for significant waste from pattern matching. It requires multiple inputs and often leaves you with a substantial amount of leftover paper. This is particularly true for complex designs like the Blue Crane Animal Mural where pattern alignment is critical.

A mural calculator, like the one Casavono provides, operates on a much simpler premise. Since the product is made to measure, the calculator's job is just to record your exact wall dimensions. There is no pattern repeat to account for and therefore no associated waste. The mural is printed as one single, continuous image perfectly scaled to your wall. This approach offers greater precision, less waste, and a simpler installation process with numbered panels that hang edge-to-edge.

How do I use a wallpaper calculator in yards?

While most modern wallpapers, especially in the UK and Europe, are measured and sold using the metric system (metres and centimetres) or imperial system (feet and inches) for North America, some materials, particularly fabric-backed wallcoverings, are still sold by the yard. If you encounter this, you will need to convert your wall measurements into square yards.

A wallpaper calculator that works in yards is performing the same basic function as any other: calculating area. To do this manually, first measure your wall's width and height in feet. Then, use the following conversion steps:

1. Calculate the total area in square feet (Width in feet x Height in feet).
2. Convert square feet to square yards by dividing the total by 9 (since 1 square yard = 9 square feet).

For example, a wall that is 12 feet wide and 8 feet high has an area of 96 square feet. To convert this to square yards: 96 sq ft / 9 = 10.67 square yards. You would then need to check the width of the material sold by the yard to determine how many linear yards to buy. This can be a complex calculation, which is why most consumer wallpaper has moved to a simpler roll-based system. At Casavono, we use inches and centimetres for all our murals to ensure the highest level of precision and make it easy for customers everywhere to order. Using a clear unit of measurement is vital when planning your wallpaper ideas room by room.

What are common wallpaper measuring mistakes to avoid?

Even with the best intentions, small measuring mistakes can lead to frustrating and costly problems. Being aware of these common pitfalls is the best way to avoid them and ensure your wallpaper project goes smoothly from the start.

Forgetting to Add a Bleed

The Mistake: Ordering wallpaper cut to the exact, precise dimensions of your wall. No wall is perfectly square, and this leaves no margin for error if there is a slight slope in the ceiling or floor.

The Fix: Always add a small amount of extra material. For Casavono murals, we recommend adding 4 inches (10 cm) to both the final width and height. This bleed is trimmed away after hanging for a flawless finish.

Measuring Around Obstacles

The Mistake: Subtracting the area of windows, doors, or outlets from your total measurements. This can leave you short on paper and makes it impossible to align the pattern correctly around the feature.

The Fix: Measure the wall as a complete rectangle, from its widest and tallest points. Hang the panel over the obstacle and then trim around it with a sharp utility knife.

Assuming All Walls Are the Same Height

The Mistake: Measuring the height of a room in one spot and assuming it is consistent all the way around.

The Fix: Measure the height of each individual wall you plan to cover. Even in the same room, heights can vary. For a single wall, measure the height on the left, in the centre, and on the right, and use the largest figure.

Ignoring Wall Preparation

The Mistake: Measuring a wall that has flaking paint, holes, or existing textured wallpaper that you plan to remove or fix. The surface you measure should be the surface you intend to hang on.

The Fix: Complete all your wall preparation before taking your final measurements. Our guide on whether you can wallpaper over paint provides detailed steps for proper prep.

What happens if I don't order enough wallpaper?

Running out of wallpaper midway through a project is one of the most common and frustrating DIY dilemmas. The consequences can range from a minor inconvenience to a major problem, depending on the type of wallpaper you are using.

If you are using traditional wallpaper from rolls, not ordering enough means you will have to buy more. The biggest risk here is that the new roll may come from a different print batch. Wallpapers are printed in large batches, and there can be very subtle colour and texture variations between them. While often unnoticeable on their own, a strip from a new batch hung next to one from the original batch can show a visible difference in colour or sheen. This is why it is always recommended to buy all the rolls you need for a single room at the same time.

This issue is completely avoided with a made-to-measure mural. Because the entire mural for your wall is designed and printed as a single order, colour and finish consistency are guaranteed across all panels. There are no batches to worry about. However, the challenge is different: since it is a custom product, you cannot simply buy a bit more. If you measured incorrectly and the mural is too small, a new mural would need to be ordered. This underscores the importance of following the measuring steps carefully and double-checking your numbers. For more guidance, our main frequently asked questions page covers ordering policies in detail.

More murals to consider

White Mountain Landscape MuralPrinted to your wall sizeOchre Dahlia Floral MuralPrinted to your wall sizeTerracotta Mountain Landscape MuralPrinted to your wall size

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