Window treatments are usually hung from curtain poles (sometimes called curtain rods). The pole sits at the top of the window and can be plain or decorative. Plain poles are best for hemmed curtains, when no part of the pole will be visible. Decorative curtain poles are suitable for tab-top curtains or any curtains that you want to draw attention to. The size of the rod you purchase will depend on the size of your window and the size of any window treatments.
Decide if you want to mount the rod on the window frame or directly on the wall above the window Take into account the size of any window treatments you may have purchased. For example, if you have purchased a valance that fits your window frame perfectly, the window frame is the best place to mount the rod.
Measure the width of your window using the tape measure.
Add 6 inches to the measurement from Step 2. The extra 6 inches will make your windows appear slightly larger. (If you don't have enough room, you can reduce this measurement to 3 inches.) For example, if your window measures 36 inches, then: 36 + 6 = 42 inches. That measurement allows for room at the side of the window when the curtains are completely open.
Make windows appear even bigger by mounting the curtain rod 6 inches above the window frame.
The rod measurement doesn't take finials into account, so if you want finials, make sure you have enough space on your wall beyond the measurement you calculated.