How to measure the window for installing a roller blind?

How to measure a window

Here we explain everything you need to know to measure your window and guarantee spectacular results

Measuring the window itself is very easy; follow these steps and it will only take you 5 minutes:

  1. Measure the width of the window frame

  2. Add at least 10 cm to the width (a minimum of 5 cm on either side)

  3. For the length, measure from the place where you want to hang the blinds to the lower end of the window frame

  4.  And now the only thing left to do is... choose your favourite blinds!

Essenza roller blind Orange

But what happens if your window has a particular feature? Or if you’d like to know a little more about the subject, with a few hints and tips? If that’s your case, continue reading and follow our advice; you’ll be delighted with the result.

Before starting to follow these simple steps, remember that it’s important to measure the place where you’re going to install the blind so that you choose the one best suited to your needs. And if you can’t find any to match your dimensions, Leroy Merlin offers the possibility of adapting all of our roller blinds to your required width.

And as we’ve previously mentioned, as well as filtering the light and guaranteeing your privacy, our roller blinds will decorate your windows and lend personality to your home.

As decorative elements, it is important to study where you’re going to install them and to take the right measurements in order to achieve the desired results and effects. So don’t forget to take a couple of things into account:

The blind width, which you’ll find on the packaging, is obtained by adding the 2.5 cm space occupied by each of the mechanisms on either side of the fabric. If your measurements are too small, you may find that the fabric doesn’t completely cover the window frame, letting in more light than you’d like. So follow our advice to guarantee that, as well as a properly installed roller blind, you’ll achieve a result you’ll love.

How to measure a window?

First step: measure the width of the opening and, therefore, of your roller blind. 

Here a number of situations may occur: 

The simplest and most common is when you have free space on either side of your window. This can provide a great opportunity to become really creative! For the most attractive results, we recommend adding a minimum of 5-10 cm to either side of the window frame. In other words, add a minimum of 10 cm to the overall width.  

If the window is next to a wall and you only have free space on one side, add at least 5 cm to the frame width. 

If there’s no space on either side or the window sits in a recess, measure the space from wall to wall and subtract 0.5 cm from either side. In other words, subtract 1 cm from the total width to ensure that the fabric will be able to move without rubbing. However, you should first of all start by checking that the recess has a minimum depth of 7 cm. Otherwise, it is a better idea to fit the blind outside the window, taking the recess as the window frame. 

And what happens if there is a headbox above your window? This is very simple to solve. If the headbox is wider than the window frame, simply substitute the measurement of the headbox for that of the frame when making your calculations.

Perfect, now you know the width. This is the point at which you could proceed to choose your favourite roller blind... but what if you can’t find one in the width you need? Very simple, you can either cut it to size at home with little more than a saw or, if you prefer, make your way to your nearest Leroy Merlin store and ask about our alteration service. The stores also offer the same service via their telephone sales line: 910 49 99 99.

How to measure a window?

Second step: measure the height, taking any obstructions into account. 

Here too different situations may occur depending on the installation.

The first one we will look at is fitting your blind to the wall. In this case you should add at least 5 cm at the top and bottom to the height of the window frame. In other words, add at least 10 cm to the total height of the window frame. It is important to remember that, if your window has elements that jut out more than 7 cm with respect to the wall, such as handles, your roller blind may knock against them. To solve this issue, you can either use brackets to give you the extra space required or install your roller blind on the ceiling. 

Ceiling installations are also a great solution when you have to cover headboxes or radiators. In this case, add a minimum of 10 cm to the distance between the ceiling and the lower edge of the window frame. 

And in the case of a recess, measure the height from top to bottom of the space... and you’re ready to go!

Unusual cases: corner windows

In windows of this kind, to calculate the width, treat each window independently, as if they were windows with a free space on one of their sides. However, in the case of corner windows, you should also subtract 9 cm from the width of one of the roller blinds so that they will overlap one another for a more attractive result.

The alternative fixing method: to the window frame

There are times, for reasons of convenience, that you may prefer to install the roller blind directly onto the window frame. In this case, you should apply the formula of adding 5-10 centimetres to either side, i.e. to the width of the glass. For the length, however, you will only have to measure the height of the windowpane. This said, once you have all of these values, check that the dimensions allow you to open the window easily, as there may be obstructions (the blind guide, the handle, etc.).

It is also very important to know how to measure them. 

We recommend that you take three measurements for the width and the height which you will use to make your calculations: the outside edges and the centre. To calculate the width, take the smallest of the three so that, if there is a wall beside the window, you’ll be sure that the roller blind won’t rub against it. And for the height, exactly the opposite, take the biggest measurement as your base.

Although these tips may seem rather obvious, it is important to follow them in order to avoid surprises and achieve a professional result: use a metal ruler, it will give a more precise measurement than other kinds. Don’t round the numbers up or down as your calculations won’t be accurate. 

And that’s it for now; if you’ve understood what you have to do, the only thing left is to select the roller blind of your choice and install them. If you’re still having difficulties, then go to the following article and we’ll take you through the process step by step.