Measure 6 inches from the left edge of the top of the window. Using a pencil, make a mark on the wall at this measurement.
Measure 6 inches from the right edge of the top of the window. Using a pencil, make a mark on the wall at this measurement.
Measure the distance between the two marks. This is the size of the pole, rod or track for the curtains. Use this measurement for a single panel that does not wave.
Divide the measurement by 2 to determine the width of two panels. Divide the measurement by three if you want three panels.
Multiply the widths by 1.5 if you want the curtains to wave when closed.
Measure the distance from one end of the window to the other. Do not measure past the window.
Divide the window measurement by 6 if you want two panels. Add that number to the window width. The final measurement is the length of the curtain rod required for the curtains.
Divide the window measurement by 3 if you want a single panel. Multiply that number by 2 and add the result to the window width measurement. The final measurement is the length of the curtain rod required for one curtain.
Divide the rod measurement by 2 to determine the width of two panels. Divide by 3 if you want three panels.
Multiply the widths by 1.5 if you want the curtains to wave when closed.