How To Measure Curtain
Measure the length of your pole between the finials (distance A) or measure the length of your track. If you do not have a pole or track, mark with a pencil on the wall the intended position of the track or pole and take measurements from this line. The track or pole is usually positioned 12 to 15 cm above the window (if there is enough space below the ceiling to allow for this) and 15 to 30cm (6”) (excluding finials) either side of the window to allow the curtain to hang clear of the edge of the window when drawn back.
For Pencil, Gathered, Pelmet, Pinch Pleat or Goblet headings if you have a pole, measure from the bottom of the curtain ring (see dashed line on the diagram above, and fig 1. below), and if you have a track, decide whether you want the curtains to hang below the track or to cover the track – and take your measurements accordingly.
As a general rule of thumb for a 35mm diameter pole, the optimum position for the curtain to hang is 4-5 cms below the centre line of the pole (see fig.1 below), with the curtain just covering the eye of the curtain ring.