Bi-fold door knobs typically have a diameter of 1-3/8 inches, the same as standard doorknobs.

Bi-fold door knobs come in a variety of styles, including round, square, and oval, and are available in a variety of finishes, such as brass, chrome, and nickel.

Installing a bi-fold door knob is a relatively simple process. First, remove the old knob by unscrewing the two screws that hold it in place. Then, insert the new knob into the hole and screw it into place. Be sure to tighten the screws securely.

When choosing a bi-fold door knob, it is important to consider the style of your home and the finish of your other hardware. You should also consider the size of the knob and the ease of use.