1. Choose recess fit or exact fit first

A recess-fit blind sits inside the window reveal. An exact-fit or face-fit blind covers the opening or frame face. Decide which style you are ordering before measuring, because the width, drop and deductions can be different.

• Use recess fit where the reveal is deep enough and mostly square.
• Use exact fit where handles, tiles, vents or uneven reveals would cause clashes.
• Check whether the supplier applies deductions or expects you to do it.
• Photograph each window and note any obstacles before ordering.

2. Measure width and drop in three places

Measure the width at the top, middle and bottom, then measure the drop on the left, centre and right. Write everything down immediately and mark which room/window the measurements belong to.

• Use millimetres and avoid rounding.
• Record all three measurements, not just the smallest.
• Check handles, vents, tiles and opening windows for clashes.
• If the reveal is badly out of square, ask the supplier before ordering.

3. Treat bay windows as separate openings

Bay windows need extra care because brackets and blind rolls can clash at the angles. Measure each section separately, check the projection of each blind type and leave enough room for controls and brackets.

• Sketch the bay shape before writing measurements.
• Mark left, centre and right sections clearly.
• Check whether neighbouring blinds can pass each other at the corners.
• Ask the supplier for bay-window bracket guidance if unsure.

4. Plan controls and child safety before fitting

Control side and safety fittings are part of the order, not an afterthought. Check which side is easier to reach, where the tensioner or cleat can be fixed securely, and whether furniture will block safe access.