Curtain measurements are always written with the width first and then the length. For example, a panel that is 46″ x 54″ is 46 inches wide and 54 inches long. Don't buy your curtains just so they're big enough to cover a window.
Width: When we list or write curtain measurements, the width always comes before the drop. Ready-made curtains are available in three standard widths: 112 cm (44 inches), 167 cm (66 inches) or 228 cm (90 inches). You should choose the width that most closely matches the size of your track or pole.
Measure the width of your window. Add 12 inches to each side, 24 inches total. Take the total number (width plus the number you added to each side) and divide that number by how many drapery panels you want in the window.
To get the measurements, measure the width of the rod from left to right. For instance, if your window measures 72” wide, you will need curtains that will give a maximum width of 144” (window width x 2 = 144”.)
All our ready made curtains are sold as pairs, and the sizes stated refer to the size of each curtain. For example, in a pair of curtains 46" wide x 54" length, there will be two curtains, each measuring 46" wide.
The actual amount of gather depends on heading styles and personal preference, but as a general rule the width of your curtains should amount to double the width of your track. This is referred to as 'two times gather'.
How wide should curtains be? To ensure that curtain panels look ample when closed, they should have a combined width that is 2 to 2.5 times the width of the window/rod. That means if you are ordering Grommet style or Rod-pocket style, the total drapery width should be at least 2 times the window/rod widths.
Keep in mind that the width measurement is flat. If you hang a 48-inch panel on a 48-inch window, there will be no fullness or draping. According to Curtainshop.com, finished curtains should be twice the width of the window, so if your window is 36 inches wide, you need panels that are at least 72 inches across.
While fashion once dictated a “flood level” bottom line for curtains—one that hung just past the window sill, short enough that it would not get wet in a flood—today, style calls for curtains to either hang down to within ½-inch of the floor or even puddle slightly.
Curtains generally come in a couple of standard sizes, depending on the type of curtain you are using. Curtain panels: 63, 84, 95, 108, and 120 inches long and 48 inches wide. Tier curtain panels: 24 and 36 inches long with widths varying in size, but the most common width is 45 inches.
Buying Standard Length Curtains
Standard curtains come in three lengths—84 inches, 96 inches, or 108 inches. "Generally, you want to stay away from the 84 inch standard curtains unless you have very low ceilings. They don't look right in most scenarios and end up being an awkward length," says Curtis.
For most curtains, two times the raw width of the window will be the perfect calculation. However, if you are using a very sheer fabric, you may want to multiply the window width by three. And, heavy fabrics may only require 1½ times the width of the window.
For a 60 inch (152.4cm) window, you need curtains with a finished width at least 1.5 times that, but better are those with twice that width and even three times the width for sheers. Therefore, for a 60 inch window, you need two panels of 60 inches each for twice the width and a luxurious gather.
Following the rule of thumb, curtains for a 96-inch window should range between 192 and 240 inches wide. To get a fuller look, aim for 288 inches wide.
It is normal for curtains to touch the floor. Some styles even need more length to produce a certain look. Using any of the curtain length styles is fine as long as it enhances the beauty of your home.
Hanging long drapes on a short window is one of the easiest ways to increase the importance of the window and bring it into proportion to the room. Short drapes on a short window call attention to the size of the window and reduce the significance of the room, window and drapery style.
The standard distance from the window casing to the end of the curtain rod (excluding finials) on each side of the window should be four to 10 inches. As a general rule, drapes will be open during the day, so make sure the curtain rod extends at least four inches on each side of the window's inside frame.
Example: If your window measures 36″ wide (window width x 2 = 72″), you need curtains that will give a minimum width of 72″ or 2 panels for that window. In this case 2 panels will give about 100″ to 120″ of width which will look nice and full.
For a 120-inch window, how wide should curtains be? Depending on the weight of the fabric and how much you want the curtains to be. At least a width and a half is what I would recommend. 180 inches is the width of each curtain.
For example, if the window is 100 inches wide, the curtains should be made to 125 inches wide in order for them to hang off the window when in the open position. For an inside-mount curtain, measure from one edge inside the frame to the inside edge on the opposite side.
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 - sheers can be 3 times the window width) to achieve a look of proper fullness.
Fabric calculations – Most curtains will require somewhere between 1 ½ and 2 ½ times fullness, depending on the heading and look you want to achieve. I always prefer to be generous and use 2 ½ times the width, skimpy curtains don't look good and you can always use any extra fabric for cushions or tie backs.
Floor length: Long curtains that go from above your window frame all the way to the floor to create a traditional, formal look. Typical curtain length for this style is 84 to 96 inches; these curtains will fall about 1/4-inch above the floor.