How to Measure Roller Blinds

Accurate measurements are the difference between a roller blind that glides effortlessly and one that binds, drags or leaks light. Follow the steps below for a flawless fit.

Inside Mount: Measure the width of your window recess at the top, middle, and bottom. Record the smallest measurement. For height, measure from the top of the recess to the sill — no deductions needed. Minimum recess depth required: 70 mm (2¾").

Outside Mount: Measure the area you want to cover on the wall or frame. We recommend extending at least 75 mm (3") on each side of the window and 75–100 mm above and below for optimal coverage. This prevents light gaps.

Tools needed

• Steel tape measure
• Pencil
• Notepad
• Spirit level

Key tips

• Use a steel tape measure for accuracy.
• Measure in three locations (top, middle, bottom) and record the smallest for width.
• Always measure width left-to-right, height top-to-bottom.
• Round to the nearest 1/8" or millimetre.

Common mistakes

• Using a cloth tape — it stretches and skews measurements.
• Measuring only at one point of the recess.
• Forgetting to confirm 70 mm of usable recess depth before ordering inside-mount.

Frequently asked questions

Should I deduct anything for inside-mount roller blinds?

No. We apply the necessary deductions in the factory. Send us the exact recess measurement.

What's the minimum window depth for inside mount?

70 mm (2¾") of clear recess depth — measure from the front of the frame to any obstruction (handles, locks, glass).

Do I round up or down?

Always round to the nearest 1/8" or 1 mm. Don't round up to compensate — that adds slack and looks sloppy.

Inside or outside mount — which is better?

Inside mount looks tailored and shows off your trim. Outside mount blocks more light and is the right call when the recess is shallow or out of square.