How to Measure for Square Bay Windows

Measuring a square bay window can sound like a daunting task, but with our step by step guide and how to video it couldn't be easier. Below you’ll find all the information you need to measure up and ensure you get the correct information you need to order your new blinds. Save money on expensive home measure visits and measure your own windows in minutes!

Video

We recommend watching our how to measure video guide first.

Choose Your Primary Position

There are two options for your square window blinds, depending if you want your front or side blinds in primary position.

Option 1

Front Blinds

This option gives greater coverage across the front of the window.

Your front blind will span the entire width of your bay window. The two side blinds will overlap the large blind at the front.

Option 2

Side Blinds

This option gives greater coverage to the sides.

Your side blinds will span the total depth of your square bay window and the front blind will sit between your two side blinds.

Choose Your Blind Type

With bay window blinds, the measurements you need to take differ for the type of blind you're looking to hang.

Step 1

Blind Type

First you will need to decide which type of blind you will be measuring for in your bay.

Step 2

Fixing Type & Rail Depth

Take note of your rail depth below for step 2 when measuring.

You also need to decide whether you will be using a top or a face fixing, as this will affect your allowances when measuring.

Roller Blinds

Top-fix bracket allowance is 50mm (for blinds up to 2000mm wide), and 70mm (for blinds over 2000mm).

A face fixing bracket is 60mm (for blinds up to 2000mm wide), and 80mm (for blinds over 2000mm).

Wooden Blinds

42mm for 35mm sized slats and 75mm for 50mm sized slats.

 

 

Aluminium Venetian Blinds

A 25mm aluminium venetian blinds has a rail depth of 30mm.

Vertical Blinds

89mm vertical blind slats have a rail depth of 70mm.

Roman Blinds

The rail depth for our roman blinds is 45mm.

Pleated Blinds

The rail depth for our pleated blinds is 35mm.

Important Note

Roller Blinds

Due to the cloth cover always being narrower then the bracket to bracket exact size, unless you have large corner window frame work, there will always be areas of glass that aren't covered fully by the blinds. This is especially noticeable if you're looking to install blackout blinds.

This applies to all roller blinds.

Measuring for a Square Bay Window with Front Blinds in Primary Position

Measuring for front blinds which span the entire width of your bay window.

Step 1

Measure the Width

Measure the full width of the long window at the front of your bay window.

Use this as the width measurement for your front window blind.

Step 2

Check your Obstruction Depth

Measure the distance from the frame of your window to the outside of any obstructions, such as handles or vents.

Make a note of this measurement.

 

Calculate total depth

The headrail depth will differ for the type of blind you're looking to hang. Find your headrail depth from the above measurements listed, and add this depth to the depth of any window obstructions, such as handles. This will give you your total depth.

For example, if your window handle protrudes 4cm from your window frame, and you're looking to measure for Wooden blinds, your calculation would be 7.5cm + 4cm. So total depth of 11.5cm.

Step 3

Mark your Total Depth

Mark the total depth of your front window blind on each side of your square bay window.

Step 4

Measure the Width

Measure from the total depth mark (which includes the depth of the blind headrail) to where you would like your side blind to finish. This is the width measurement of your side blind and repeat this step for both side blinds.

Step 5

Measure the Drop

Measure the drop of your square bay window in three places.

Use the smallest measurement as your drop for all blinds.

Step 6

Final Step

Now enter your width and drop measurement, then select Recess as your sizing option and repeat this process for each blind you need to cover your sqaure bay window.

Deductions

We will make a small deduction to the width of your blind when you select the ‘Recess’ sizing option to accommodate the brackets.

Measuring for a Square Bay Window with Side Blinds in Primary Position

Measuring for side blinds whih will span the total depth of your square bay window.

Step 1

Measure the Width

Measure the full width of the windows at the side of your bay window.

Use this as the width measurement for your side window blinds.

Step 2

Check your Obstruction Depth

Measure the distance from the frame of your window to the outside of any obstructions, such as handles or vents.

Make a note of this measurement.

 

Calculate total depth

The headrail depth will differ for the type of blind you're looking to hang. Find your headrail depth from the above measurements listed, and add this depth to the depth of any window obstructions, such as handles. This will give you your total depth.

For example, if your window handle protrudes 4cm from your window frame, and you're looking to measure for Wooden blinds, your calculation would be 7.5cm + 4cm. So total depth of 11.5cm.

Step 3

Mark your Total Depth

Mark the total depth of your side window blinds on each side of your square bay window.

Step 4

Measure the Front Window

Measure from one of the pencil marks on one side to the other on the other side. The distance will be the width of your front window.

Step 5

Measure the Drop

Measure the drop of your square bay window in three places.

Use the smallest measurement as your drop for all blinds.

Step 6

Final Step

Now enter your width and drop measurement, then select Recess as your sizing option and repeat this process for each blind you need to cover your square bay window.

Deductions

We will make a small deduction to the width of your blind when you select the ‘Recess’ sizing option to accommodate the brackets.