You might be surprised to learn that the actual length of a wiper arm is longer than its designated length. That’s because the industry standard approach is to designate wipe arm length as the straight line distance from the center of the pivot shaft to the center of connection to the wiper blade The bridge width between the driver and idler of a pantograph arm is measured “center to center” too.
But what about when there’s a bend in the arm? Pretty much the same advice applies when there’s a bend in the wiper arm. To determine the arms length, simply measure the straight line distance from the center of the pivot to the wiper blade connection.
So, just think “center to center” whenever you measure a wiper arm and you’ll do fine.