With a measuring tape, paper and pencil, you can calculate the amount of fabric necessary to create fresh, new curtains. Simple multiplication will then tell you how much material you need to form drapes that will impact your living environment with colour and style. So start measuring and imagine the finished product hanging at your windows.
Measure the window width. This number includes the total area that you want to cover with fabric.
For the sake of example, assume this measurement is 84 inches wide and a fuller appearance is desired.
Multiply by 2 for standard fullness, by 1.5 for less fullness and 2.5 for a fuller appearance.
In the above example, the measurement would now change to 210 inches. (84x2.5)
Add 15 inches to this facing flat width. Seven inches are for a 3.5-inch return, the side section that goes to the wall, on each edge. The other 8 inches are for two hems, using 4 inches, on either side. This total measurement is called the cut width.
In the example, 210 inches wide plus 15, equals 225 as the cut width.
Divide the cut width by the fabric width. Standard fabric widths available at retailers are 45, 54, and 60 inches. Round up to the nearest whole number. This is called the WOM, or width of material.
The WOM of the example is 225 divided by 54-inch wide fabric or 4.1--rounded up to the nearest whole number, this is 5 yards of material.
Measure the total length of the curtain area and add 10 inches. Eight of these are for the hem and 2 inches are for the casing and heading at the top.
As an example, the total cut length is 78 inches, plus 10, equalling 88 inches.
Multiply the WOM by the cut length. This result is the fabric needed.
Example: 5 multiplied by 88 is 440 inches. Divide this by 36 inches per yard, and you will need 12.22 yards of fabric.
For pinch pleats you will multiply by 2.25 in step number 2.