Question: what is the standard width of drapery fabric?
Answer: Curtain fabric is always sold with the length of the curtain (the drop) coming off the roll and the width of the fabric is used for the width of the curtain. Curtain fabrics are 137 cm wide as standard. Some come wider, some narrower, so it's worth checking your fabric, but the average is 137 cm so we'll go with this.