Window blinds measuring guide

Measuring for your new blinds couldn't be simpler. It's an easy way to save lots of money and takes just minutes; you'll wish you'd done it sooner! All you have to do is follow our easy, step-by-step guides below.


Standard Windows

Recess Fitting
This is the measurement you need to take if you want your blind to fit inside the window recess. Measure the full width and height of the recess [the size of the hole if you like] and we will make the appropriate deductions to ensure a perfect fit.

  • Measure in 3 places for both the width and the drop, use the smallest measurements
  • Don't make any deductions, we will do that for you to ensure your blind fits perfectly
  • Use a metal tape measure, cloth ones can stretch and give you inaccurate measurements
    measuring for recess blinds

Exact Fitting
This is the measurement you need to take if you want the blind to hang outside the recess overlapping the window. In this case we will make the blind to your specified size with no deductions.

  • Measure the exact width of the area you would like the blind to overlap. To minimize light leakage we recommend that the blind overlaps the window recess by at least 70mm at the top and 50mm each side
  • The overlap at the bottom of the blind is a matter of personal choice but please take into account obstacles such as radiators
    If you are replacing an existing blind with one of the same size simply measure the blind and specify exact fitting, we will make you one the same size
    measuring for exact blinds
  • Top Tip: Measuring for your roller blind is slightly different because the overall width of the blind including the brackets is approx. 3.5cm wider than the fabric. With this in mind you can choose to measure from where the brackets will sit ('bracket to bracket') or the area the fabric will cover ('fabric width').

Square Bay Windows

First choose the blind type you would like to fit into your bay window, for example Vertical blinds. Different types of blind should not be mixed.
Next read about exact and recess measurements here.
Step 1

  • Measure window A first and write this down as a recess measurement. Mark where the front edge of the headrail would be when fitted, with apencil. These vary by blind type (see table below).
  • You will also need to take into account anything that protrudes from the window, such as handles and add this measurement on. For example when allowing 2cm for handles and choosing a standard Roman with 2.5cm headrail the measurement you’d mark would be 4.5cm from the
    window (2+2.5=4.5cm).

Blind type 

Headrail depth

Roller -25mm barrel (for widths of
blind under 2m)
Roller - 36mm barrel (for widths of
blind between 2m and 2.4m)
Roller - 42mm barrel (for widths of
blind over 2.4m)
Roman – standard headrail 2.5cm
Roman – deluxe headrail
Vertical 89mm 8.5cm
Vertical 127mm 10.5cm
Pleated 20mm 2.1cm
Woodweave 6cm
Venetian 15mm 3.5cm
Venetian 25mm 3.5cm
Venetian 35mm 4.5cm
Venetian 50mm 5.5cm
Wood Venetian 25mm 5cm
Wood Venetian 35mm 5cm
Wood Venetian 50mm 7cm

Step 2
Measure from the pencil mark you made to represent the front edge of headrail on window ‘A’, across window ‘B’ and write this down as an
Step 3
Repeat step 2 for window ‘C’. (Note: if you have a ‘closed’ bay window i.e. you have a wall at the end