Window valances are a quick way to add a pop of texture and color to any room in your home. While valances can be expensive, you can quickly and easily make them yourself with a few basic sewing supplies and beginning sewing knowledge. Because windows come in all widths, calculating the amount of fabric you need may be a bit of a challenge. With some simple measurements and math, you can quickly figure out how much fabric you need and make your valances.
Install the rod you will use to hang your valances according to manufacturer's instructions. Measure the length of the window from the top of the rod to the top of the lower window casing. Measure the width of the window from the outside edge of each side of the window casing. Write down these measurements.
Figure the base height of your window valance. To do this, take the measurement length you wrote down and divide it by three. For example, if your window length as measured is 42 inches, you would divide by three to get a base length of 14 inches. Add 3 inches to this measurement to allow for seam allowances and a curtain rod casing. In the example provided, the new height would be 17 inches. This new measurement is your final measurement for your window valance.
Figure the base width of your window valance. To do this, take the width measurement you wrote down. If you are making a gathered valance, multiply this number by two to allow for gathering; if you are making a tailored valance, leave this number as is. For example, if your base width is 60 inches and you are making a gathered valance, your new measurement would be 120 inches. If you are making a tailored valance, it would stay at the 60-inch measurement. Write down this measurement and add 2 inches to this number to allow for seam allowances. This new number is your final width measurement for your valances.
Calculate how many valance height measurements you can fit onto the width of your fabric. To do this, take the width of your fabric (usually either 44 or 60 inches) and divide it by your final height measurement. For example, if you use 44-inch fabric and have a 17-inch height measurement, you could fit two full valance heights onto the fabric If you use 60-inch fabric, you could fit three valance heights onto your fabric. Write down the number of valance heights you can use on your selected fabric.
Divide the final valance length measurement by the number of valance heights you can fit onto your fabric. For example, if your final valance length measurement is 122 inches and can fit three valance heights on your fabric, you would divide 122 by three to get 40.67. Round this number up to the nearest whole number. This number is the number of inches of fabric you need for your valance.
Convert the number of inches you need to yards by dividing the inch measurement by 36. For example, if your rounded number of inches is 41 inches, you would divide by 36 to get 1.13 yards. Round your number up to the nearest quarter yard. In this case, it would 1.25 yards. Purchase the amount of fabric you need for your valances.