How to Measure for Blinds

Firstly, you’ll need to decide whether you are fitting your blind inside or outside of the window recess. The brackets supplied with our roman blinds are suitable for both fixing types.

With large or medium windows, blinds are often fitting inside the window recess. With smaller windows, blinds are regularly fitted outside the recess to retain more light.

There are also instances where the blind would need to be fitted outside the recess, regardless of preference. These are:

When the recess is less than 7.5cm deep

When the window opens inwards

When the window itself isn’t straight (variance in width or height of more than 2cm)


Standard windows

Measuring for a blind to fit inside a recess

Make sure that your window recess is at least 7.5cm deep.

Measure the width of your window in 3 positions, noting any protrusions such as dado rails and tiles. Write down the smallest measurement. Do the same for the drop, measuring in 3 positions and noting any protrusions. Again, write down the smallest measurement.

These two measurements are the width and drop of the blind. Enter these measurements when creating your roman blinds, making sure that you choose the blind type ‘INSIDE RECESS’. This is important as we will make your blind approximately 1cm smaller in the width so that it fits comfortably inside the recess.


Measuring for a blind to fit outside a recess

Measure the width of the top of the window, adding on approximately 5-10cm either side for the blind to overlap the window.

Measure the drop from where you want the blind to sit above the window to where you want it to finish below. Again, we would recommend ensuring the blind extends approximately 5-10cm above and below the window.

These two measurements are the width and drop of the blind. Enter these measurements when creating your roman blinds, making sure that you choose the blind type ‘OUTSIDE RECESS’. This is important as we will make your blind to the exact measurements that you provide.


Fixing height

This is a measurement, to the nearest cm, from where the top of the blind will be positioned to the floor. This measurement allows us to understand the approximate chain length required.


Bay windows

Roman blinds in bay windows are usually fitted within the recess. Please follow the instructions below for angled and square (box) bay windows.

Measuring for a roman blind to fit inside a bay window recess

Measure the drop of each side of the bay window in a minimum of two positions, writing down the smallest measurement. This will give us the drop measurement for each blind. Should you wish for the blinds to be level when lowered, use the shortest measurement for all blinds.

Cut rectangular sections of card measuring 10cm x 5cm, placing them on your windowsill as shown in the diagram below. These cards represent the ends of the blind brackets. If you notice any protrusions, for example window handles, move the cards further away from the window to allow for clearance. Make sure that you have enough room at the top of the recess too to mount the blinds. With the cards in the correct position, look up to the top of the recess and check that the blind could be fixed from this position. Note that this measuring method assumes top fixing only.

Use a pencil to gently make a small mark on the windowsill at the position where the paper meets the window frame. Do a quick test at this point to make sure you can remove any marks from your window sill before you proceed! Continue to do this at each corner of the bay window, e.g. at A, B, C, D, E & F (diagram below).

Measure as follows to work out the width of each blind.

Angled bay or square bay (point to point)

Left hand blind - measure from A to B

Centre blind - measure from C to D

Right hand blind - measure from E to F

Square bay (overlapping)

Centre blind - measure from A to B

Left hand blind - measure from C to D and deduct 2cm

Right hand blind - measure from E to F and deduct 2 cm

(The deduction for the side blinds is to allow extra space for the centre blind to stack when raised).

Provide all width and drop measurements when placing an order and ensure that you choose ‘INSIDE RECESS’ for your blind type.


When you have placed an order, make sure you read our guide to fitting your blinds.

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