How To Calculate Wallpaper Needed

How To Calculate Wallpaper Needed

How To Calculate Wallpaper Needed

Introduction to Wallpaper Calculation

Do you seek to redecorate your home, office space or perhaps transform your child's room with some whimsical wallpaper? Right off the bat, one particular question has probably popped up in your mind, just how much wallpaper do I need?

Unlike painting, wallpaper comes in rolls and it's essential to understand how much we'll need to effectively cover the walls without wasting materials or falling short. Here, we'll discuss how you can accurately calculate the amount of wallpaper required for your project.

The Importance of Right Calculation

Calculating the quantity of wallpaper needed is not just about avoiding wastage - it's also about budgeting. Most of us have a limited budget for our redecoration or renovation projects. Accurately determining the needed wallpaper can allow us to allocate our resources more effectively.

Variables to Consider

There are numerous variables to consider when doing these calculations such as the size of your room, the height of your walls, the size of your windows and doors, and the pattern of the wallpaper. Each of these plays an integral role in our calculation for the amount of wallpaper necessary to complete the project.

Room Size

The length and width of your room, combined with wall height, determines the total area of wall space that needs to be covered. This can be calculated by multiplying the length of your room by the height of your walls for each wall in the room.

Windows and Doors

Doorways, windows, and any other features interrupting the wall must be accounted for in your calculation. Despite needing no wallpaper, these areas still take up space on your wall. Hence, subtracting their area from your total wall area will refine the accuracy of your calculation.

Wallpaper Pattern

Patterned wallpapers are trickier to calculate than plain ones due to the need to match patterns, which often results in offcuts and wasted paper. Typically, more patterned wallpaper is needed compared to plain wallpaper, not forgetting the wallpaper pattern repeat size also impacts the total needed.

Making the Calculations

To make the calculations easier, we will provide a step-by-step process later in the tutorial. Just remember, careful calculation and accurate measurements are key to mastering the art of wallpaper estimation.

Understanding Wallpaper Rolls and Measurements

In order to accurately calculate the amount of wallpaper needed for your project, you must first understand wallpaper rolls and their measurements. Ignoring this step can lead to wastage or potentially lacking wallpaper when you require it the most.

Standard Wallpaper Roll Sizes

Wallpaper rolls typically come in two standard sizes: single and double rolls. A single roll typically measures 21 inches wide by 16.5 feet long and covers around 25 to 28 square feet. A double roll, on the other hand, is 21 inches wide, but 33 feet long, and covers approximately 50 to 56 square feet. It's essential to remember that while the length of a double roll is twice that of a single roll, its width remains the same.

European Wallpaper Roll Sizes

In contrast, European wallpaper rolls are a bit larger. They are typically 21 inches wide and approximately 33 feet long, covering roughly 57 square feet.

Calculating the Wall Size

Before purchasing wallpaper, you need to measure your walls. To do so, measure the height and width of each wall using a tape measure. Multiply the height and width of each wall to get its square footage. Sum up the square footage of all your walls. This is the total coverage area.

Calculate The Number of Wallpaper Rolls Needed

Once you know the total coverage area for your walls, divide that number by the coverage area of the roll size you plan to purchase. This calculation will indicate how many rolls you'll need. It's a good practice to buy an extra roll to account for any mistakes or future repairs.

Considering Pattern Repeats

If your chosen wallpaper has a repeat pattern, you'll need to account for that in your calculations as well. Patterns can be random match, straight match, or drop match. You should add the repeat size to the height of your wall for repeating patterns to calculate the correct amount of wallpaper.

Random Match Patterns

This pattern repeats but not in a specific sequence. Therefore, there's very little waste with this type of pattern, making it a cost-effective choice.

Straight Match Patterns

For a straight match, the pattern matches across the width of the wallpaper. You may need additional wallpaper to align the patterns.

Drop Match Patterns

In drop match patterns, the pattern is staggered across the width of the wallpaper. This pattern may lead to more wallpaper wastage and may require more rolls to correctly match the pattern across the room.

Understanding wallpaper rolls and measurements before starting your project will save you both time and money, and prevent the frustration of running out of wallpaper midway through the project or ending up with excessive leftover wallpaper.

Assessing Your Room's Dimensions

The first step to figuring out how much wallpaper you need is to accurately assess the size of your room. This requires measuring the height, width, and length of your walls. Let's break down these steps in more detail.

Measuring Your Wall Length and Width

To start, you'll need to measure the length of each wall. Use a tape measure to get the dimensions from one corner of the wall to the other. Make sure to record your measurements in feet or meters, depending on your preferred unit of measure. After measuring the length, proceed to measure the width of the wall, from floor to ceiling. It's important to be as accurate as possible, as even small inaccuracies could lead to a significant discrepancy in the amount of wallpaper needed.

Measuring Your Wall Height

The next step is to measure the height of your room. This should be done from the floor to the ceiling. While doing this, ensure to take into account any slopes or uneven surfaces that might affect the measurements. It's recommended to measure the wall height in multiple spots to account for any inconsistencies caused by uneven flooring or ceilings.

Factoring in Doors and Windows

It's also important to take into account the size of any doors and windows in your room, as these areas will not be covered by wallpaper. Measure the width and height of each door or window and subtract the resulting area from your total wall area. Remember, it's always better to overestimate the area a bit, as it's better to have a little extra wallpaper than not to have enough.

Calculating the Total Wall Area

Once you've taken all the necessary measurements, you can calculate your total wall area by adding the areas of each individual wall. You can calculate the area of a wall by multiplying its width by its height. Don't forget to deduct the area of the doors and windows.

Calculating the Number of Wallpaper Rolls

With the total area of your room calculated, you can now figure out how many rolls of wallpaper you'll need. The number of rolls needed will depend on the size of the roll and the pattern of the wallpaper, so it's essential to refer to the manufacturer's instructions. Generally, you'll divide the total room area by the coverage area of one roll of wallpaper.

Account for Pattern Repeats

If your wallpaper has a pattern that needs to be matched, you'll likely need more than if you were using a plain or random pattern wallpaper. This is because some of the wallpaper will be wasted in order to line up the pattern correctly. Check the wallpaper's labeling for information on pattern repeat and factor this into your calculations.

The Importance of a Buffer

Lastly, always allow for some error or damage by buying extra wallpaper. A common rule of thumb is to buy 10-15% more wallpaper than your calculations suggest. This will cover any mistakes during the installation process and provide a little extra for future repairs if necessary.

Factors to Consider Before Calculating Wallpaper

When it comes to wallpapering your home, one of the most important aspects is knowing how much paper you need. Before setting out to calculate the wallpaper you need, there are a few key factors to consider.

Wall Measurements

The first factor is the size of the area being papered. This includes measuring the height and width of the wall space, ignoring doors and windows for the moment, since you’ll be more accurate if you initially assume the wall is a complete rectangle.

Understanding Your Wallpaper

You need to familiarize yourself with the dimensions of the wallpaper roll you want to buy. Different rolls have different widths and lengths, and this influences the total coverage. Also, consider the pattern of the wallpaper. Patterned wallpapers might require extra allowances for the drop repeat and pattern matching.

Features in the Room

Windows, doors, fireplaces and fitted furniture all change how much wallpaper you will need. Subtract their measurements from your total wall space to give a more accurate idea of how much wallpaper will be required.

Extra Allowance for Wastage

It's vital to include an extra allowance for the paper wasted when cutting, and any accidental damages. The general guideline is to add an extra 10-15% to your total paper needs to cater for this.

Complexity of the Room

The shape of the room and the complexity of the wallpapering task can heavily influence how much paper is needed. Wallpapers for rooms with lots of corners and intricate details will require more allowances compared to a simple square or rectangular room.

Professional or DIY?

Are you planning on doing the job yourself or hiring a professional? A professional might be more efficient and waste less paper, but if you are DIY-ing for the first time, you might need extra for learning and mishaps.

Future Needs

Have you considered future needs? It's a good idea to buy a little extra to cater for future repairs, and in case the wallpaper is discontinued, you will have some residue for any pressing needs.

By considering these factors, you will be well-prepared before you begin your calculations for the wallpaper needed for your space.

Step-by-step Guide to Calculate Wallpaper Needed

Decorating the walls of your home with wallpaper can significantly change the feel and look of your space. Choosing the right design is the starting point. The critical, and arguably trickier stage, is calculating the amount of wallpaper needed for your project. We have broken this process down into a simple, easy-to-follow guide.

Identify Your Wallpaper Roll Coverage

A typical roll of wallpaper covers around 57 square feet (5.3 square metres). However, designs differ, and it's crucial to check the specifications of the wallpaper you have chosen. Often, the roll's coverage is mentioned on its packaging or the manufacturer's website. If not, you can calculate it by multiplying the width and length of the roll.

Measure Your Walls

The second step involves measuring the length and height of the wall or walls where you plan to hang your wallpaper. For this task, you'll require a tape measure. The width of the wall multiplied by its height gives you the total square footage.

Calculate the Total Wall Coverage

With your measurements at hand, you can calculate the total square footage of your walls. If you’re papering more than one wall, add up all the individual wall footages to get the total square footage needed. Don't forget to consider windows and doors in your measurements as such areas will not need wallpaper.

Factor in any Repeat Patterns

If your chosen wallpaper features repeat patterns, you may need more wallpaper to ensure the patterns line up correctly. Check the roll to see the repeat length and factor this into your calculations.

Determine the Number of Wallpaper Rolls Needed

Divide the total wall coverage by the coverage of one roll of wallpaper. Always round up to the nearest whole number even if you get a decimal. It's better to have extra wallpaper than run out during the project.

Consider Wastage

Finally, it’s always recommended to order an extra roll or two to account for any errors, damage or future repairs. This step ensures that you won’t end up short during the decorating project, or if an accident occurs in the future, you will have an exact match to replace any damaged areas.


While estimating, take into consideration that older homes may have higher ceilings or irregular wall sizes. For such cases, always order extra to be safe. Moreover, it is also essential to double-check all measurements and calculations, as some may opt for a professional opinion.

Common Mistakes in Calculating Wallpaper Amount

Calculating the right amount of wallpaper for your room can be a tricky task, especially if you're doing it for the first time. Even those with experience can sometimes make mistakes. It's crucial to accurately calculate the wallpaper required, but equally important is to avoid common errors. We will guide you through some of these most common pitfalls.

Not Measuring Rooms Correctly

One of the most common mistakes is incorrectly measuring the area of the room. This error can lead to a miscalculation of how much wallpaper you need. Don't forget to measure the length, width and height of your room, not excluding doors, windows and unusual shapes. Using a precise measuring tool and double-checking your measurements will minimize any risk of error.

Not Accounting for Pattern Repeats

Another regular oversights in calculating wallpaper amounts is neglecting pattern repeats. Patterns often require matching and alignment. If your wallpaper has a large pattern repeat, you may need extra wallpaper to match the design correctly. Always refer to the product information to find out the pattern repeat and make sure to include this in your calculations

Forgetting About Waste Factor

When cutting and hanging wallpaper, there's always some waste. Most people forget to include the waste factor in their calculations. Usually, it is wise to add approximately 10-15% extra for wastage, depending on your level of experience and complexity of the room.

Mixing Wallpaper Batches

Every batch of wallpaper can have slight color variations which may not be noticeable until hung side by side. Mixing batches, i.e., using wallpaper from different production batches can lead to noticeable differences on your wall. Always ensure the wallpaper is from the same batch and don’t forget to order some extra from the same batch, in case you need more.

Not Considering Future Needs

Finally, many forget to consider future needs. What if the wallpaper gets damaged and needs to be replaced? Keeping an extra roll from the same batch can avoid headaches later. Always order a bit extra to account for future damage or replacement needs.


By being mindful of these common mistakes, you can ensure you calculate the correct amount of wallpaper required. The key is to measure accurately, consider all factors, and always order a little extra.

Tips for Calculating Wallpaper for Complex Shapes and Sizes

Calculating wallpaper for complex shapes and sizes can often present a tricky challenge. However, with a few practical tips, you can make the task considerably easier. Here are some pointers to keep in mind when you're sizing wallpaper for complex spaces.

1. Take Exact Measurements

Measure your room thoroughly first, including the length, width, and height for all walls. When measuring around windows and doors, add them to your total and then subtract them later. It's better to have too much wallpaper than too little.

2. Rectangle Rule

Many rooms or parts of rooms can be considered as rectangles. If you have an L-shaped room or an alcove, consider them as separate rectangles for easy calculation.

3. Factor in Windows and Doors

As you measure your room, remember to take into account the space taken up by windows and doors. Usually, you'd subtract one roll for a door and half a roll for a window.

4. Consider the Pattern Repeat

If your wallpaper has a pattern that needs to be matched, it will require more material to ensure all the patterns align perfectly on your wall, potentially increasing waste. Always consider the pattern repeat in your calculations.

5. Don't Forget the Trim

If you plan to have a trim, factor it into your measurements. A wallpaper border or trim will often need additional material.

6. Brush up on Your Math

In wallpaper hanging, there's a fair bit of math. If you're intimidated by the calculations, there are plenty of online calculators available that can help, or ask a professional for help.

7. Keep in Mind Unseen Complications

Finally, always remember to account for unforeseen complications. There might be patches of wall that need extra wallpaper, or you might make a mistake and need additional material. It's always wise to order a little extra, just in case.

8. Go for Professional Help if Needed

If the calculations seem too overwhelming or if you're dealing with unusually shaped rooms and walls, don't hesitate to seek help from a professional. They have the expertise to handle complex measurements and can ensure you have the right amount of wallpaper for your project.

Ensuring Adequate Wallpaper Supply for your Project

When you've made the decision to install wallpaper, it is crucial to ensure that you have an adequate supply to complete your project. With careful planning and calculation, it’s possible to minimize waste and avoid unnecessary costs, while ensuring a seamless installation process.

Determining the Area

The first step towards ensuring you obtain a sufficient quantity of wallpaper is to calculate the total area of the walls to be covered. Measure the height and length of each wall, and multiply these measurements to determine the square footage. Don't forget to deduct the area of doors and windows from your total to ensure an accurate estimate.

Accounting for Pattern Match

Wallpapers often have patterns that need to be aligned between sheets, and this pattern match can influence the amount of wallpaper you'll need. When a wallpaper has a straight match, patterned or not, no allowance needs to be made for wastage apart from trimming. However, wallpapers with a drop match pattern will require additional wallpaper to ensure that patterns align correctly on each strip.

Catering for Extra

Always include a little extra for mistakes, or in case you want to alter a particular area of the room. A general rule of thumb is to add an additional 10-15% to account for this, as well as any potential trimming or matching needs. This could consist of supernumerary batches if you have a large project or simply additional rolls for smaller tasks.

Ordering Wallpaper

Once you have made these calculations, you'll have a good idea of the quantity of wallpaper roll you’ll need for your project. Most wallpaper is sold in rolls, and knowing your square footage will help you determine how many rolls to buy. Remember that ordering a few extra rolls at the start is often beneficial as dye lots can change from one batch to another, and it may be difficult to find your exact pattern in the future.


Taking a little extra time to properly calculate your needs can save a lot of time and expense down the road. Keep in mind it's always better to overestimate than underestimate when it comes to wallpaper. You'd rather have a roll left over than run out in the middle of your project.

Wallpapering your home can be a fun and rewarding task if you prepare well. With the aforementioned guide, you should be able to meticulously calculate your wallpaper needs and ensure a sufficient and timely supply for your project.