How to measure your windows for curtains and blinds

Measuring your windows for a quick curtain change can be more complex than you might think, so we've put together a handy little guide with everything you need to know

Blind and curtain fitting measurement

There are many different options available for your window dressings and replacing them can seem like a daunting task. To help you correctly measure your windows to ensure the perfect fit we’ve got some top tips from DirectBlinds.

How to measure for blinds

Firstly, it’s best to invest in a metal tape measure as cloth tapes aren’t accurate enough, and you will need a pen and paper to record the sizes.

Measuring to fit blinds
Little Green taped, 50mm, from £83.99
© DIrectBlinds

Before you begin, look for any possible obstructions to the clear working of your blind, such as inward opening windows, handles or part tiling and make sure you allow for these when deciding where to measure.

If you would like your blinds to fit inside your window opening this is called a recess measurement.

To measure inside your window recess, follow these steps


Step 1

Measure the inside width of your window in three places. The narrowest measurement is your recess width.

Step 2

Measure the inside length or drop of your window in three places – the shortest measurement is your recess drop.

Step 3

Most blind manufacturers will reduce your recess sizes to ensure the blinds fit within the opening, so it’s important to bear this is mind when measuring.

For blinds that hang outside your window recess, this is referred to as an exact size.

Step 4

For exact size fitting blinds, do the following:

Measure the width where you want the blind to be, allowing for a 10cm-15cm overlap each side to work out the exact width.

Step 5

Measure the length where you want the blind to be, again allowing for a 10cm-15cm overlap but this time for both the top and bottom. This is the exact drop length.

Step 6

For exact measurements, blind manufacturers will make your blinds to these exact overall dimensions and make no allowances.

Note: When measuring roller blinds please note that the cloth or fabric width will be 3cm narrower than the overall exact blind width.

Step 7

How to measure for curtains


Measuring to fit curtains
Ferle tangerine, from £97.01
© DirectBlinds

To start with, if you have an existing curtain pole or track make sure you measure the whole width, not just the window opening, being careful not to include the end ornaments in your measurements. For those of you measuring a track with an overlap don’t forget to add it to the end to end width.

If fitting a new track or pole make sure it is approximately 15cm above the window and 20cm wider each side of the opening, so the curtains can draw clear to let more light in.

If you would like your curtains to drop to the floor, measure to 1cm from the floor. For curtains touching the window sill, also measure 1cm above. However for curtains to fall below a window sill measure roughly 20cm below, or if there is a radiator underneath measure 3cm above the top of the radiator.


Top tip

To achieve the most accurate measurement always measure in a few places as a lot of tracks, poles and windows aren’t quite level.

Use the shortest measurement to avoid the curtains dragging on the floor.


Information courtesy of DirectBlinds, for more information please visit