For grommet curtains you will need to take into account the placement of the grommet.
Height to put curtain rod.
This is a traditional height though you can cheat an inch or so either way depending on the height of your ceiling and the length of your finished curtains.
For standard drapes that hang on either side of a window the typical height is halfway between the top of the window.
When you hang the curtain rod high it will make the window appear taller.
Use these tips to make sure you place your rods at the right height.
For cathedral ceilings leave approximately four to six inches above the window trim as a guideline.
Hanging curtain rods high above the window frame adds height to the wall and works best with long panels or drapes.
Go high a rule of thumb from architectural digest is that curtains should be hung between 4 to 6 inches above the window frame so install your curtain rod accordingly.