How to Measure for Bay Windows | 247 Guides


Bay windows are a wonderful part of British architecture, allowing improved views of your road and neighbours, they create more light and space, and have been a staple of traditional homes since they came into vogue in the 1800s. 


When you want to be able to enjoy your own helping of made to measure style, it’s super important to ensure you get the best fit possible. To give you the expert helping hand you need, we’ve put together plenty of tips from the experts that will ensure you get your bay windows measured like a pro.


Jump to:

Measuring up Angled Bay Windows

Measuring for Square Bay Windows

Our depth projection guide

How to choose the best blinds for your bay window?



A brown wooden blind in a living room bay windowA brown wooden blind in a living room bay window

Measuring up - The right tools for the job.


First things first, you’re going to want to dust off your toolkit. Don’t worry about anything too complicated though because all you’re going to need is:


  •  A piece of paper for your measurements
  • A sharp pencil
  • A tape measure.
  • Your chosen blind brackets*


*these are not 100% needed, but can make the job a bit easier.


Make yourself a strategy brew, and you’re now ready to get started!


Quick Step Summary


When measuring for bay windows — there are few steps you'll need to take & a few considerations.  These are as follows :-


  • Determine which blinds you may like up at the window — from wooden blinds, roller blinds, Roman blinds and even curtains, there is a lot of different options available.  Each blind can come with its own challenges, so we'd recommend checking out the depth projection guide & the guides further down the page.
  • Order your samples — These can be on the way to you whilst you measure up.  Of course, you'll need to settle on the most suitable blind type for your window - A guide further down this page has a nice summary for you.
  • Measure up your bay window — Whether your bay window is angled, square or even has uPVC windows, this is the most important step, after determining the blind type and depth.
  • Always Take Obstructions Into Account — This is the bit people miss most often, so we’re going to start with it. Bay windows will likely have window handles and air vents that complicate matters, and if you don’t allow for them, then they’re going to foul your blinds as you raise and lower them. You want to know how far the obstruction sticks out, which means you need to note down the distance between the front of the window frame and the outer edge of the obstruction. It’s likely to be the same for every handle, but check each of them just to be sure.
  • Use bits of paper or card to help you — Mark out the expected blind placements with card or paper, using the projection guide to determine the bracket meeting points.
  • We can help — We can post out examples of your chosen blind bracket — Simply give us a buzz on 01484 443790, and we'll try to help as much as we can.


Measuring for Angled Bay Windows.


So angled bay windows not only look super stylish, but are actually the easiest of the two main bay types to measure for.  It's all about the angles here, so you'll need to determine your chosen blind type and mess around with the bracket meeting points.


If you look at the image, you can see we've labelled each window up from left to right: - A, B and C.  We'd recommend you do the same to allow you to follow your measurements accurately & sketch everything out, so you know 100% which measurements are for which blind.


Following our useful blind projection guide here, this determines for you the blind depth.  Using this, you need to determine where you are going to be fitting each blind.  Some people like to have the blinds meet equally on the corner, or some prefer to measure the largest window (B)  first and then fit the surrounding blinds (A & C) to suit.  We recommend the former; fitting your blinds to meet each other, as this ensures the most 'even' look at avoids the side windows from having larger gaps than needed.


Once you've determined the meeting point, we'd recommend that you'd order these blinds as a recess size.  This means that we'll take a small tolerance off the total width of the blind.  If you don't want to do this, then order blind size, but at least deduct a 5 mm tolerance for your overall blind size bracket (making a 1 cm gap between the brackets meeting each other).  See our recess deductions guide with the window depth guide further down to see our deductions.


An Angled bay window graphicAn Angled bay window graphic

Measuring for Square Bay Windows


Measuring for square bay windows is super similar to its angled counterpart, you just have less 'play' in account of the tighter angle.  


Fitting of the brackets is again up to you, you can have an overlap of one (we'd suggest the main window for this, which is B in the diagram), or have them meet together.  The latter means that you should have less of a gap compared to the overlap method, but again this depends on  your preference, the blind you've chosen to fit and the final position of the brackets.


A graphic showing a square bay windowA graphic showing a square bay window

What are our blind depths & Recess reductions - 247 Mini Guide


So we've made a super easy-to-follow depth projection guide which can be downloaded by clicking the picture.   This will tell  you the blind depth, and should be used to determine the bracket meeting points.


Bay window projection downloadable guideBay window projection downloadable guide



Blind TypeWidth (mm)Drop (mm)
Roller Blinds50
Roman Blinds*50
Day Night Blinds50
Double Roller Blinds50
Vista Blinds50
Wooden Blinds100
Venetian Blinds100
Vertical Blinds1010


Correct as of Sept 2021.


*It is important to note that Roman blinds, due to their design, thicker fabric, plus lining, can have a large “stack height” and “stacked depth” when adding the headrail depth on.

Please contact us with your sizes, so we can advise the approx. total depth, before you order for your Bay Window.


Which blinds are best for a bay window?


So, we will provide a quick summary of each blind type & their various benefits.  However, for a more extensive guide, including info on oriel and uPVC window types, we've made a master guide here!


Roller Blinds


Roller blinds offer a wide range of fabrics, styles, and patterns to allow you to really stretch your interior design skills. 


However, these blinds come with a bit of a snag if you're fitting in bay windows, there is a small gap between the fabric and the end of the blind where the bracket fit.  This is an overall gap of approx. 3.5 cm.  This means that the gap where the blinds fit will be more noticeable for this blind type. 


However, all is not lost!  You can choose to have these blinds what we call 'B mount'.  This is where instead of the fabric falling over the back of the roll at the back, it will fall over the front towards the inside of the room.  This will lessen the gap at the blind meeting points, however it does mean if you've opted for blackout fabric, the 'light bleed' (this is the light that naturally gets in around the blind), around the fabric will be increased.


Wooden Blinds


Though wooden blinds look amazing up in bay windows, they also present a few things to be mindful about.


The most popular 'slat' sizes you can order these in are 35 mm & 50 mm.  These larger sizes do mean fewer slats in the blind.  However, this can mean a larger headrail.


We'll also need to know if your order has blinds fitting within the same room, this is because we would need to ensure that the blinds are made with the same number of slats.  This is not always guaranteed, so give us a call and email to confirm prior to ordering.


The top of the blinds will also need thinking about - As standard our blinds are treated as one, not a trio, so the pelmet (the headrail cover), will need adjusting to suit your needs.  It's likely you'll need to cut down to suit your bay window angle and sizes, but again let us know, and we'll help you through it!


Roman Blinds


Roman blinds make for a smart choice as their fabric fully covers the headrail.  This means  any gap between the blinds are reduced. 


However, do keep in mind that this blind type gathers, which is sometimes referred to as the 'stack' size.   If you're unsure, email in your sizes, with your chosen fabric and lining type, and we can confirm the stack depth for you.  Keep the above in mind, especially for window handles and where the blinds will meet at the corner points!


Drill-Free blinds - For uPVC windows.


This means you'll need blinds that require no drilling to fit.  Currently, we have Perfect Fit and Neat Fit blinds, which in turn are available in various 'blind types'; Aluminium Venetians, Wooden and Pleated.  Both Perfect Fit and Neat Fit utilise the window beading, and require a mailable rubber seal to enable you to fit the brackets.  See our guide here for more information! 


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