1) Measure the width of your window.
2) Add 3" to that measurement*
3) Choose the next larger size awning from the list below.

Available sizes: 27", 33", 39", 45", 51", 57", 63", 69", 78"

*this is the minimum required measurement. You can put a larger awning on a smaller window, however, plastic hollow wall anchors (included) may be required if your brackets do not attach to the studs normally surrounding a window.