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.
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”.)
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.
In the US, the standard curtain width would be 54”. But generally, it ranges from 50-58”. Some curtain manufacturers even go for as long as 108”. Again, knowing the curtain width is as essential as the length because you have to align it with standard curtain sizes.
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.
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.
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'.
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.
There's a simple calculation to work out how much curtain fabric you need. First, multiply the track/pole width by your chosen fullness (eg. Pole width 150cm x 2.5 = 375). Next, divide that figure by the fabric width, which is typically 137cm (375 divided by 137 = 2.73).
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.
If you are interested in stationary panels, you will want your curtains to be long enough to lightly brush the floor, but not so long that they bunch up in a pile. A good rule of thumb is for your curtains to break anywhere from a ¼” to ½” from the floor, similar to a break in pant legs on your shoe.
How Wide Should Curtains Be? To ensure that panels look ample and drapey when closed, they should have a combined width that is 2 to 2½ times the width of the window. Exceptions: If you're hanging curtains just to frame a window and don't intend to shut them, you can round down to 1½ times the width.
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. To create the illusion of a wider window, extend the rod up to 10 inches beyond the window's frame.
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.
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.
The width of a bolt is usually 45 or 60 inches (1,100 or 1,500 mm), but widths may include 35–36 inches (890–910 mm), 39 inches (990 mm), 41 inches (1,000 mm), 44–45 inches (1,100–1,100 mm), 50 inches (1,300 mm), 52–54 inches (1,300–1,400 mm), 58–60 inches (1,500–1,500 mm) and 66 inches (1,700 mm), 72 inches (1,800 mm) ...
MEASURE WIDTH
The curtain should measure 1 ½ to double the width of the window for fullness.
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.
Measure from the rod to where you want the curtains tohang. Mine falls just below the bottom trim. Add 2 inches to get the height of your panels (3 inches for the top and bottom hem minus one inch for the drop of the curtain clips).
In the Living Room
The windows behind the sofa are a great location for cafe curtains, too, as seen here in a room from designer Sara Gilbane. They're low maintenance; no need to open them in the morning for light or close them in the evening for privacy.