Curtain Sizes
The curtain sizes used by manufacturers and suppliers vary widely. 
The following information should give you an idea of some common sizes employed. Use the following as a guide on how to determine which curtains fit your needs.
Curtain Measurements
All curtains are measured by width and drop (i.e., 46” width x 54” drop). If you’re buying pairs, the size referred to is usually for each curtain, not the two of them.
The measurement is done when the curtain is laid down (no gather). So if you buy a 45” x 54” for a pair of curtains, you’ll be getting two of that size.
How to Get the Right Curtain Sizes
Start by measuring the track pole width. If you haven’t done any fitting, the ideal pole position is 15 cm or 6” above the window. It should also extend half a foot (6”, 16 cm) on both sides of the window. This excludes the finials.
To achieve the full look, the pole fit should be up to 48" or 122 cm. In this case, the curtain should be 46" (117 cm). If the track or pole is 48"’ – 66", the curtains should measure 66" (or 168 cm). If the pole is 66" – 90" (168 – 228 cm), the curtain should be 90" (228 cm).
When measuring curtain sizes, the width of both curtains needs to be 1 ½ times the track / pole. This does not include the finials. When it comes to curtain length decide if the curtains will fit the sill. Also consider if it will be below the sill or at the floor.
For sill length curtains, it should be 1/2" (1.5 cm) over the sill. If the curtains will be below the sill, the finish should be 6" (15 cm) below. For floor length curtains, the finish may be 1/2" (1.5 cm) from the ground surface.
Other Tips for Getting Curtain Sizes Right
When making measurements, a metal tape measure will be helpful. For the width, make sure there is a 75 mm (3") space on either side. When measuring the curtain length, keep the following in mind.
If you are using the 3” tape heading on the track, measure the track from the top. For a curtain pole, start measuring from the eye of the ring. If using the eyelet heading, start from the pole top. That is about 1.5” at the top of the pole.
Bear in mind that the designs of curtains and their finishes are subject to personal preference. However, it’s important that you keep the basic measurement techniques in mind.
Curtains come in a variety of textures and fabrics, lace being one of the most popular. This will add or reduce the curtain’s weight, even if the sizes are the same. Keep this in mind especially if you have to install and clean them yourself.
No mater how lovely the curtains are, it won’t look good if the dimensions are wrong. Take the time to pick the right curtain size and your windows will look perfect.
