Width - Measure the width of your track. Drop - Measure from the top of the curtain track to where you want the curtain to finish. ie, 1.60m, 2.05m, or 2.20m.
Width - Measure the inside window frame from edge to edge and allow enough space at each side for stacking, normally 20-50cm each side depending the width of your window. Drop – Tracks suggested to be installed 5-10cm above the window, now choose which drops you prefer, ie, 1.60m, 2.05m, or 2.20m.