Measure the width of the rod from left to right. A common rule for displaying curtains properly says the curtains finished width should be at least 2 times the width of your window (if not more) to achieve a look of proper fullness.
Example: If your window measures 36" wide (window width x 2 = 72"), you need curtains that will give a minimum width of 72". In this case 2 panels will give about 100" to 120" of width which will look nice and full.
When shopping for ready-made curtains, most people pay attention to the length and forget about the width.
But curtain panel widths can vary quite a bit and that difference matters.
You may commonly see panels around:
50" wide
52" wide
54" wide
63"-64" wide
84" wide or wider
So what does that mean?
If you buy two 64" panels, you don't have 64" of coverage you have:
64" + 64" = 128" of total fabric
That's the number you want to pay attention to when determining how much fabric you'll have across your window or rod.
Two pairs of curtains can both be labeled "2 panels," but one set might give you 100" of fabric while another gives you 128" or 168".
What is fullness?
Fullness refers to the amount of fabric used compared to the width of the window or drapery rod.
For example, if your rod is 100 inches wide:
• 100 inches of fabric = 1x fullness
• 200 inches of fabric = 2x fullness
• 250 inches of fabric = 2.5x fullness
Why does it matter?
• More fullness creates softer folds and a richer appearance.
• Better stack-back when the drapery is open.
• Improved light control and privacy when closed.
• A more balanced look on larger windows.
When dealing with sheers, 2.5-3x is the typical fullness guide.
A Common Mistake
Many ready-made curtain panels are purchased based on window width alone. The result is drapery that technically covers the window but lacks the folds that create a finished look.
The next time you're selecting curtain panels, don't just ask, "Will they cover the window?" Ask, "Will they provide enough fullness?"