Many wallcovering retailers provide online calculators for estimating how much wallpaper is required. However, these can be inaccurate because they do not factor in pattern repeats and deductions for windows, doors and cabinets.

It is therefore best to use the hand calculation method, which is easy and accurate. This will help you avoid over-ordering and wasting money.

Use a Tape Measure

Whether you are planning to add an eye-catching accent wall or wallpaper your entire home, it is important to measure accurately and order enough rolls of wallpaper for complete coverage. Using a tape measure, begin by measuring the height and width of each wall. Record each measurement and write them down in a notepad. Leave skirtings (baseboards) out of the measurements unless you are planning to wallpaper them too. For more info I’ll suggest you visit the website wallpaper singapore.

Most wallpaper guides suggest taking into account doors and windows when calculating your measurements. However, Hogan advises against doing this as it can lead to a waste of material. He suggests removing the window and door features from your measurements and multiplying the remaining wall area by the wallpaper’s coverage per roll.

This number will allow you to estimate how many rolls of wallpaper you will need. It is a good idea to add 10% on for wastage as this will save you the hassle of having to order additional wallpaper midway through your project.

Measure the Width of the Walls

The most important step when calculating how much wallpaper you need is measuring the width of each wall. Then, multiply the total width of all the walls (excluding doors and windows) by the height of each wall to get a measurement in square meters of the area you want to cover with wallpaper.

Some wallpaper guides suggest calculating the number of usable, floor-to-ceiling strips on each roll of wallpaper. However, Hogan warns that this can leave you short of your needed amount. “You will end up wasting some paper as you trim to line up the pattern and to create clean seams,” she says.

For patterned wallpaper, you also need to factor in the pattern’s vertical repeat, which can be found on your wallpaper sample or under product specifications on the supplier’s website. Add the wallpaper’s repeat to the combined wall widths to obtain a calculation in inches of how many “drops” you need. Always round fractions up to avoid under ordering.

Measure the Height of the Walls

You can use a wallpaper estimator online to help determine how many rolls you need for your room, but this is also something you can do by hand. Start by adding up the widths of the walls and recording this value, then measure the height of each wall, and add these values together.

Once you have the total height of your walls, add this to the height of your pattern repeat (found on your sample or in the product description) and multiply by the number of full drops per roll (provided in the wallpaper specifications). Remember to round up here as you don’t want to end up with a short amount of wallpaper that will require trimming.

Next, subtract any doors and windows from the total height of your walls. This will give you the total room area in square meters, which is the measurement used for wallpaper and paint. Remember to always keep at least 10% of extra wallpaper on hand for touch ups and unforeseen hiccups.

Measure the Perimeter of the Room

If you’re working with a square or rectangular room, finding the perimeter is a simple matter of adding the lengths of the walls together. If you have a rectangle that’s 18 feet long and 14 feet wide, for example, adding those two numbers together gives you the perimeter of the room at 60 feet.

If your room is more irregularly shaped, however, you’ll need to manually measure the perimeter of the space. Start by choosing two perpendicular walls and measuring their lengths. Then, take your own paces and multiply the number of steps it takes to walk from one wall to the other (assume each step is 3 feet).

If you’re using wallpaper that requires trimming around windows or doors, it may be helpful to subtract the measurements of these features from the total area measurement of the room. This will help you avoid ordering too much wallpaper, which can be expensive to ship and install.