Whether you make your own curtains, buy off the shelf or order custom, knowing the right measurements for your window is key.

• Decide what kind of curtains you want: floor-length formal drapes, informal tab-tops or café curtains.

• Decide where the curtain rod will go. You'll probably want it about 6 inches above the window frame, but you might want it higher or lower or, for a dramatic look, on a tall, deep window - inside the frame.
  
  
• Decide how much coverage you want. Curtains usually extend about 6 inches above the window frame, 2 to 3 inches on each side, and 2 to 3 inches on the bottom. Consider how much light you want to block - probably a lot if the window faces east and you like to sleep in - and how much privacy you want the curtains to provide.
  
  
• Use a tape measure to measure from the curtain rod to the desired bottom point, and from side to side. Multiply the side-to-side measurement by two to allow for generously full curtains.
  
  
• Make sure the salesperson or decorator understands that these are desired finished dimensions of your curtains, not the dimensions of your window. (It is of course helpful to provide window dimensions as well.)
  
  
• And if necessary, do not hesitate to consult an expert.