How Do You Identify Unknown Door Hardware?

Start with location, movement, and mounting

Do not start with a brand name. First record where the part sits, what the door does when the part moves, and how the part attaches.

What you can see	Likely hardware family	Measure next
Metal leaves joined by a pin at the door edge	Hinge	Leaf height, leaf width, thickness, corner shape, hole pattern
Lever, knob, or thumbturn through the door face	Cylindrical or mortise lockset	Door thickness, backset, bore or case dimensions
Arm connecting the door to a box at the top	Door closer	Mounting pattern, arm type, door width and weight
Plate across the lower face of the door	Kick plate	Door width, plate height, edge clearance
Horizontal bar used to unlatch an exit door	Exit device	Door width, device length, trim, fire-door label

If the opening has a fire label, electrified hardware, panic hardware, or an accessibility requirement, stop before modifying it and confirm the listed assembly and local requirements.