Sister built a new house last year and (like me) she was lacking in the curtain department. So for Christmas I told her that I would make curtains for several of the rooms in her house. I’ve only finished two of them and its four months after Christmas, but who’s counting? Luckily Sister didn’t mind!
First, I measured the width of her window casing from the outsides. Then I added two inches for each side and half an inch for each seam allowance. (5 inches total) I added two inches to each side since that was how far the pocket rod I was going to use stuck out from the wall. If you want your curtains to be much wider than the window casing you would need to account for that in this measurement.
I cut a rectangle piece of fabric and lining the width of the measurement above and 17 inches long. (This was just an estimate based on how far I wanted the curtain to hang down and allowing for the seam.)
I made the straps using a coordinating fabric folded and stitched (right sides together) as shown below. Then iron and flip. I used a safety pin to attach them together so that I could easily adjust the length if I needed to.