Measuring door hardware: how to determine the PC size

What is the PC size?

The PC size is the distance between the center of the lever hole and the center of the cylinder hole of a lock. This measurement determines which door hardware will fit your existing lock. Common sizes include PC55 and PC72. The PC size is different from the backset: the latter indicates the distance from the faceplate of the lock to the center of the handle.

How to measure the PC size

Measuring a PC size is simple. Use a tape measure or ruler and measure from the center of the lever hole to the center of the cylinder hole. With a door plate, you can determine the distance between the center points of the two openings. Do not measure from the edge of the plate or the rosette, as those dimensions can vary per model.

Common PC sizes

You will encounter various PC sizes for interior doors. PC55 and PC72 are common versions, but other sizes also exist. Therefore, always check the size of the existing lock before ordering new hardware.

Avoid an incorrect order

An incorrect size means that the new door hardware will not fit the existing lock properly. In addition to the PC size, therefore, also check the lock type and the door thickness. When in doubt, it is wise to measure the size again.

Practical tip: take a photo of the lock while measuring and write down the measured distance. This way, you will have the correct information at hand when choosing new door hardware later.