What tools do I need to measure for blinds?

You’ll need a durable tape measure (such as a metal tape measure or laser), a notepad or device for writing down measurements, and a pencil to mark out where the drilling points or headrail will go. For blinds which fit perfectly in the recess, a depth gauge can also help. If the window is high up, you may also need a step ladder , with someone safely footing it for you.

What if my window measurements don't exactly match the size of the blinds available?

If your windows aren’t a uniform size, you could opt for made-to-measure blinds to fit the space. Some blinds are sold as ‘adjustable’, meaning you trim them to size. You could alternatively choose ‘outside fit’ blinds, which cover the entire window space, and which will be larger than the frame.

Do I need to get a professional to measure for blinds?

No, as long as you have an accurate steel tape measure or laser measure, and you can easily access the window space, it’s simple to measure for blinds yourself. Always take three separate measurements - the top, middle and bottom - for both the width and drop. If in doubt, re-measure to ensure accuracy.

How do I measure for blinds if my windows are not perfectly square?

It’s common to have windows which aren’t uniform in size, so an outside mount blind might be a better fit. If you’d like recess fit, though, take the three different measurements for the width and height and choose the smallest measurement to ensure accuracy and smooth operation of the blind.

Can I use the same measurements for different types of blinds?

The measurements will be different for different blind styles. Inside recess or outside recess styles will need different sizes. Also, roller blinds have a mechanism which is larger at the top, so the ‘total width’ is different from the fabric width. Venetian blinds and Roman blinds will be different again. You should only start measuring after you’ve decided on a blind style.

Measuring Blinds Correctly

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Measuring a window with a measuring tape to fit blinds

Measuring for window blinds can be a straightforward job, but it’s not always easy if you don't do it regularly. Whether you’re a homeowner, DIY enthusiast, or even a tradesperson, this handy guide will walk you through how to measure windows for blinds, including how to measure for roller blinds, and how to measure blinds accurately if the window isn’t perfectly straight.

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Importance of Accurate Measurement for Blinds

It goes without saying that blinds need to perfectly fit the window space in order to function correctly. It’s not just about aesthetics - ill-fitting blinds won’t block out the light as planned, they may not operate smoothly, lead to a lack of privacy, wasted material costs, and provide poor insulation in the colder months. This is why it’s essential to read expert advice, source the right tools, and use an accurate tape measure before starting the job.

Step-by-Step Guide on How to Measure for Blinds

Your choice of blinds will vary with the aesthetic that you’d like to create, but some styles might better fit your home and space. Before you start, there are two main mounting options for installing blinds in your home:

Inside recess (also known as recess fit) - these blinds fit perfectly within the window frame, which is ideal for smaller spaces. They can also offer good value alongside reasonable light blocking, privacy and insulation, but they require reasonably uniform window recesses and accurate measurements.
Outside recess (also known as outside mount or exact fit) - this style sits over the window and covers the wall and trim around it, creating a larger focal point. If you’d like blackout blinds, or you have window recesses which are too narrow or uneven, these can be an ideal choice for fitting yourself.

You’ll need to decide on your blind style before you start measuring, as each is measured and mounted in a different way. Whichever style you choose, you’ll need to measure:

The window recess (the space around the window which is hollowed out in the wall) to see if they’re a uniform size all around. This may impact your choice of blind style.
The width of the window.
The drop (how long the blind needs to be).
If using an outside recess blind, the area around the window too.
You’ll also need to check for potential obstructions, such as protruding handles or if window sills are in constant use. Recess blinds require an empty sill to draw down.

So, whether you would like a simple inside recess roller blind, a sleek Venetian, or a timeless Roman blind, read on to find out how to measure blinds yourself.

The secret to how to measure blinds accurately is determining whether you need to measure for ‘recess fit’ measurement (if you want the blind to go inside the recess) or the ‘exact fit’ measurement (if you want an outside recess blind to cover the whole window and opening). This depends on the look you want, as well as the space available.

Inside recess (recess fit)	Outside recess (exact fit)
Fits inside the window area (inside).	Sits over the entire window (outside).
You’ll need to measure the window recess width and height (the hole).	You’ll need to measure outside the window frame area, choosing the width and height that you wish to cover.
Perfect for small window areas.	Can be used for larger, ornate windows.
Sleek, simple and saves space as they don’t protrude out. It can also offer great value.	More of a focal point, so it’s possible to use more elaborate styles.
Block out most light, but light can protrude around the edges.	This style can block out light fully.
You’ll need enough of a recess to fit inside.	It can be fitted to most windows, even with narrow recesses.
Requires exact measurements to fit.	Measurements can be adjusted based on how large you want the blind to be.

How to Measure for Roller Blinds

Roller blinds can be a great value option, coming in a wide range of colours and designs, and this classic style can be either recessed fit or outside recess. However, they can present a unique challenge in measuring, as you have to factor in the mechanism itself alongside the actual fabric width. You’ll need to measure the entire width of the blind (known as total width, including the headrail), then calculate the fabric width (the size of the actual blind material). Many curtain manufacturers suggest subtracting a small margin on each side, of around 5-10mm, so that the curtain can roll up and down easily.

TOP TIP: Don’t forget to factor in window handles when measuring, as very protruding handles may stop the blind from working smoothly. In this case, you may want to fit an outside recess roller blind. This also works well if you don’t want to disturb items on the windowsill when the bling is drawn.

How to Measure Windows for Blinds

Firstly, it’s essential to measure for blinds using either a metal tape measure or a laser measure to avoid any irregularities.

Using your steel tape measure (or laser measurer), take the measurements at three different points - the top, middle and bottom of the blind area - for both width and height (drop) to ensure accuracy. Note all measurements down to the exact mm.
For recess fit blinds, you’ll then take the smallest measurements to make sure the blind fits snugly when covering the window.
For outside fit, measure the wall area where you want the blind to cover, adding some extra at each edge to help improve aesthetics and block out the light. When considering the drop, don’t forget to factor in radiators or other furniture which may sit below.

Common Mistakes to Avoid When Measuring for Blinds

If you’re not used to fitting blinds, it’s important to note down the measurements exactly and ensure that you’re using metric rather than imperial measurements for the correct fit. If you’re having your curtains made-to-measure, check with the company before you supply the measurements, as some automatically add or remove fabric lengths for you to ensure the fit (you may simply need to provide the total width/drop). Avoid using fabric tape measures, as these can stretch and provide inaccurate measurements. Also, don’t forget to factor in any potential handle obstructions, and be sure to always measure the three different areas for an exact fit.

Key Takeaways For How To Measure For Blinds

When measuring blinds, the most important thing is to first decide whether you’re having recess fit (inside mount) or outside recess (outside mount), as these will determine where and how you measure for the correct fit. Always measure three times in the three areas, in both width and height, and choose the smallest dimension for recess fit blinds to ensure they operate smoothly. Accurate measurements will ensure your blind fits perfectly and creates a focal point in the room for many years to come.

Measuring Blinds Correctly - FAQs

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