Definition: All door hardware fits doors between 1 3/8" to 1 3/4" thick. If your door is thicker, you will need to specify its thickness.
Most interior doors are 1-3/8 inches thick, while most exterior doors measure 1-3/4 inches. But what if your door is thicker than these standard measurements? Don't worry, you will just need additional (longer) components to connect the hardware from one side of the door to the other. This is commonly referred to as a thick door kit. Some door hardware manufacturers provide these for free, while others require the customer to make an additional purchase. Contact Factory Direct Hardware's customer service to determine which one you will need for your door hardware.
(Most interior doors are 1-3/8 inches thick, while most exterior doors measure 1-3/4 inches.)