Measure window blind width at the top of the recess

The greatest worry when you  purchase a window blind is whether the blind will fit when it is made. Most window blinds are fitted inside the window recess.

You should always use a steel tape measure. Cloth tape measures can stretch  and give an inaccurate measurement.

We measure the window width inside the window recess at the top.
The drop is measured in at least two positions and we use the shorter of the measurements. All of the dimensions are given to the nearest millimetre.

Measure the drop in at least two positions

For vertical blinds top fix brackets are normally used when fitting inside a window recess.

We use the recess sizes and any clearances required to allow the blind to fit the recess are made during the window blind manufacturing process.

Venetian blind measured between half tiled recess

Venetian blind allowing for tiles at bottom of recess

This advice is correct when measuring vertical or roller blinds because the fabric is not quite as wide as the recess. However venetian blinds are as wide at the top as they are at the bottom. Therefore an allowance has to be made to provide clearance for the tiles if the recess is partially tiled at the bottom.

You must measure venetian blinds at the bottom when the recess is partially tiled.

When measuring partially tiled recesses, measure tightly between the tiles and take off 15mm.  If you don’t, the blind will clash with the tiles when the blind is lowered.