How to measure for roller blinds (inside and outside the recess)

Getting ready to measure for a new roller blind can feel a bit nerve-wracking. I get it.

Because we make each blind to your exact sizes, we can’t accept returns if you get the measurements wrong. We don’t offer a measuring service, so you’ll be doing this yourself. But it’s straightforward once you know the rules.

To measure for a roller blind, you first decide if it will hang inside or outside the window recess.

For a blind inside a recess, you measure the width and the drop in three places, then use the smallest of each measurement.

Below are both methods and the mistakes to avoid.

What you need before you start

You need a metal tape measure and a pencil.

Your first decision is where the blind will hang.

There are two options:

1. Inside the recess: The blind fits neatly within the window opening.
2. Outside the recess: The blind is fitted outside the window opening and overlaps it. This is the ‘exact size’ option on the order form.

If you’re thinking of an inside fit, check you have at least 5cm of clear depth between the front of the recess and any obstructions.

Oh, don't forget to look for obstructions, such as tiles, that stick out into the space.

The three-point rule for a recess

The name of the game here is to find the narrowest and shortest points.

Here’s what to do:

• For the width: Use your metal tape measure to get the width at the top, middle, and bottom of the recess. Write down the smallest of these three numbers. If tiles stick into the recess, measure between them and use that as your width.
• For the drop: Measure the height from the top of the recess to the window sill on the left, in the middle, and on the right. Again, write down the smallest of the three.

That's it.

When you order, you enter these two smallest measurements and select ‘inside recess’ on the product page. We then take about 12mm off the width you give us so the brackets fit.

Our full roller blinds measuring guide has diagrams for all these steps if you need a visual.

Choosing your own overlap

Fitting a blind outside the recess is an option if you want to block more light. With this method, you decide the final size of the blind.

You’ll measure the width and drop you want the finished blind to be, including the overlap.

I recommend an overlap of about 5cm on each side of the opening, so 10cm added to the total width.

A bigger overlap lets in less light.

For the drop, allow at least 7cm of overlap at the top so the headrail is covered.

If your window sill sticks out more than 5cm, measure the drop at that point.

When you order, you enter these final dimensions and select ‘exact size’. We will make the blind to those exact measurements, with no deductions.

Three common measuring mistakes to avoid

These are the mistakes I’d watch for.

The first is measuring a recess in one place only. Take three and use the smallest.

The second is the units on our order form. You can enter millimetres or centimetres, and if you set the wrong unit, your blind could arrive far too big or too small. Check it before you add to basket.

If you're ordering for a whole house, measure every window. Ones that look identical can differ.

A note on ordering made-to-measure blinds

Production can start very soon after you place an order, so double-check your numbers before you confirm.

We make all our blinds to a tolerance of plus or minus 3mm. Every order also has mismeasurement protection: a discount on a re-order, which varies by order, so email us at hello@blindstyle.co.uk to find out what it would be.

What about bay windows or very wide windows?

Bay windows have their own guides, for both angled bay windows and square bay windows.

For very wide windows, you might want to hang two blinds side-by-side. To do this, decide where the split will be (usually the centre, or on a window frame mullion) and mark it with a pencil. Then, simply measure for each blind separately as if it were in its own window.

There will be a small gap between the two fabrics because of the brackets.

With your measurements ready, see the designs in our roller blinds collection. I always recommend ordering a few free samples to see how the colours and textures look in your own home.