What length shower curtain rod should I buy?

Measure the wall-to-wall distance of your shower opening and pick a rod whose adjustable range comfortably brackets that number near the middle, not at its maximum extension. Standard tub openings are around 54 to 60 inches, while the wide-range telescoping rods here span anywhere from 28 up to 80-plus inches for stalls, alcoves, or non-standard spaces.