Getting the right curtain measurements is crucial for a polished look. First, decide between an inside mount (inside the window recess) or an outside mount (on the wall above the frame). For an inside mount, measure the exact width and height inside the recess at three points, using the smallest measurement. For an outside mount, decide how far you want the rod to extend beyond the frame for optimal light blockage and a spacious feel. The rod is typically placed 4-6 inches above the window frame. Measure the desired rod width and the length from the rod to your preferred endpoint (sill, below sill, or floor). Always use a metal tape measure for accuracy, write down all measurements, and double-check them. For curtain rods, measure the window width and add necessary overlap. For blinds, inside mount requires precise recess depth; outside mount needs width and height of the area you wish to cover. Remember, "measure twice, order once" to avoid costly mistakes.