Ready Made Curtains are made in standard sizes, unlike custom curtains which are made exactly to size. Ready Made Curtains sizes and colors may vary by manufacturing run. It is best to purchase everything you need at the same time.   The rod pocket for Ready Made Curtains is usually 1.5". The rod diameter should be no more than 13/16" or the rod will not go into the pocket. If this measurement is different, it will be noted.   Determine how much fullness you need by measuring the width of the rod, or where you will mount the rod. Allow 1.5 to 2 times the window width for fullness (gathers). Fullness is a matter of personal preference, you may want more. Less would be a rather flat look. Once you have chosen a pattern, you can tell how many curtains you need to satisfy your fullness preference. Usually, a Ready Made Curtain is designed to fit for width on a single window. For instance, if your window is 40" wide, times 1.5, equals 60" of curtain: If your selected pattern is 60 " wide, then you need 1. If you wanted 2 x full (double-full) 80" of curtain - you have to decide whether to use 2, which would be 120", or 3 times full. If your selected pattern is 45" wide, you will need 2 and they will be 2+ full. Length: Lots of choices- Just put valances at the top. Or swags. A tier or cafe curtain, (from the half-way point down), with or without a valance. Curtain Panels - starting anywhere and ending anywhere.