A: total, expected width of the blind.
B: total height, including the headrail.
We do not deduct from your sizes!
We recommend you deduct 10mm from the width (A) for blinds fitted inside a recess.
You can also deduct 15mm from the drop to lift the blind away from the sill/floor.
State all sizes to the nearest millimetre. Measure the recess width and drop in at least three places. Always give the narrowest measurements.
Always measure using a steel tape measure and check for any obstructions in the fitting area.