Published February 7th, 2024

Door Hardware 101 Guide

Written by Level Home Staff | Fact Checked by Eric Schoneberger

Door hardware 101: Parts, types, standard dimensions & more

Door hardware might not be something you think about every day, but it’s helpful to know the correct terminology when you’re talking to a professional. Whether you’re looking to update your home’s curb appeal, need to replace some old hardware or just troubleshooting, our helpful guide to door hardware will make the process easier by giving you the right language to use.

In this article, we cover:


What are the levels of door hardware?

Product grade levels are a standard defined by the Builders Hardware Manufacturers Association (BHMA) and the American National Standards Institute (ANSI) to help consumers select the right hardware for their needs.

The current ANSI grading system has 3 grades and indicates more about the hardware than just security:

  • Grade 1 - is the highest performance

  • Grade 2 - moderate performance

  • Grade 3 - basic performance


Where a piece of hardware falls on the ANSI grading scale is determined with extensive testing in the following 6 categories:

  • Operational

  • Cycle

  • Strength

  • Security

  • Material Evaluation

  • Finish Tests


The BHMA grading system is simplified for consumers and rates locks with letters A, B, or C based on security, durability, and finish. The best possible BHMA grade is AAA.

Common types of door hardware

The basic types of door hardware include:

  • Door Knobs/Handles - The mechanism that enables you to open and close the door is called a door knob, handle, or lever depending on the type of hardware you have. Learn about the most common types of door knobs & handles.

    • What are the parts of a door knob called? The essential parts of a door knob include:

      • Escutcheon - general term used for the decorative metal plate around a door handle/knob

      • Latch Strike Plate -this is the metal plate that is on the frame of the door where the latch enters to secure the door shut

      • Latch Plate or Face Plate - this is the metal plate that is on the door surrounding the latch

      • Latch - the piece of metal that extends from the door into the frame. This is what keeps your door shut and what is moved out of the way when you turn the handle or knob. Generally these are spring-action and will automatically extend when not acted upon or obstructed. The most common standard backset lengths of the latch are 2 ⅜ and 2 ¾

      • Spindle - also called plunger, tongue, torque blade; this is an inner rod that connects the knob/handle to the latch assembly

  • Door Hinges - The mechanism that attaches a door to the frame, enabling you to open and close the door. There are different types of hinges, but generally there are 2 - 3 per door opposite the knob-side.

  • Lockset - This term generally refers to the components that make up the complete assembly of the lock system, including the lock mechanism, knob or handle, keys, strike plate, face plate, and other accessories.

  • Deadbolt - The part of a lock that extends from the door into the frame, engaged by turning a key or knob on the lock, rather than by the action of a spring.

Parts of a door

  • Kick Plates - A protective covering at the base of a door to prevent damage from shoes.

  • Door Frame - The supporting structure around a door, consisting of the jamb, sill, and head

  • Door Jamb - The vertical piece of the door frame running along the side of the door

  • Door Head - Sometimes called head jamb; refers to the top of a door frame that sits horizontally above the door

  • Sill - The bottom of a door frame that sits horizontally against the floor

  • Threshold - Also sometimes called a saddle, this is the protective covering for the sill and is usually sloped outwards to help keep wind, water, and other elements from entering

  • Rail - The top rail, lock rail, and bottom rail of a door are the horizontal pieces situated at the top, middle, and bottom of the door respectively

  • Stile - The lock stile and hinge stile are the vertical pieces of a door on either the lock side or the hinge side

  • Doorway - The opening you walk through

  • Mullion or Mull - The vertical pieces of the door that run parallel to the stiles, typically making up the middle of the door. There are multiple mullions on doors that have a lock rail interesting horizontally

  • Door handing - The direction your door swings. This is important to know so you can purchase the correct hardware to fit your door. Otherwise, it may be misaligned, the handleset could be upside down, or the door may not close properly.

  • Casing - The decorative trim around a door

  • Weatherstripping - Material used to insulate the gaps around a door

  • Astragal - The hardware that is used to seal the gap between double doors, different from the mullion because it is attached to the door itself

  • Panels - The decorative square or rectangular pieces that site between the rails and stiles
  • Sidelite - The thin window butted against an entryway door
  • Door Sweep - Similar to weatherstripping, a small piece of material at the very base of a door that helps seal the air gap

Standard door hardware specifications

Your doors may differ from the standard specifications, so it’s always a good idea to measure the one you’re working with before purchasing hardware. It’s sometimes possible to modify parts of the door like the bore hole, though it’s much easier to make sure you know what size hardware fits your door before you buy. Other factors to consider are the materials your door is made of, for example, hardware needs for wood and metal doors will likely differ.

  • Backset - Most residential doors in the US will have a backset of 2 ⅜ inches or 2 ¾ inches. This is the measurement of the space between the center of the bore hole and the edge of the door
  • Latch Plate Mortise - This is the term used to describe the indentation, recess, or pocket in the edge of the door where the latch plate or face plate sits. It should be just deep enough that the plate is flush with the edge of the door, while these are commonly cut during installation they tend to be around 1/8 inch deep.
  • Face Bore or Bore Hole - This is the larger hole that contains the lock or knob/handleset assembly. Typically in the US these are 2-1/8 inches in diameter but can vary greatly depending on the type of door hardware installed.
  • Edge or Cross Bore - This is the smaller hole that goes from the edge of the door to the bore hole, where the latch mechanism is housed. Again, these can vary greatly depending on the type of hardware being used but typically measure 1 inch in diameter for standard doors in the US.


Now that you’re more familiar with the terminology used to describe doors and door hardware assemblies, you can feel confident in measuring for the parts you need or talking with a professional. When you’re ready to shop for new door hardware, consider our selection of smart locks and handlesets to elevate your entryway.