A lockset is the complete assembly of hardware that allows you to open, close, and secure a door. It includes the handle or knob, the latch mechanism, the strike plate on the door frame, and (in locking versions) a keyed cylinder. When you buy a “lockset” at a hardware store, you’re getting all of these parts as a single, matched package rather than purchasing each component separately.
Parts of a Lockset
Every lockset shares the same basic anatomy, whether it’s a simple closet knob or a heavy-duty keyed entry set.
The knob or lever is the part you grab. Knobs are round and require a twisting motion. Levers are straight or slightly curved bars that you push down, making them easier to operate if your hands are full or you have limited grip strength.
The latch bolt is the moving metal piece that extends from the edge of the door into the frame, holding the door shut. Most locksets use a spring bolt: a spring keeps the latch extended, and turning the handle compresses the spring to retract it. A deadbolt, by contrast, has no spring. It stays locked or unlocked until you physically turn a key or thumb turn to move it.
The strike plate is a metal plate screwed into the door frame with a rectangular hole (called the box) that receives the latch bolt. It reinforces the frame so the bolt has something solid to seat into rather than just wood.
The cylinder is the core of a keyed lockset, the part where you insert your key. Inside the cylinder, a row of spring-loaded pins sit at different heights. When the correct key slides in, its ridges push each pin to the exact right position, allowing the cylinder to rotate and the bolt to move. An incorrect key leaves at least one pin out of place, and the cylinder won’t turn.
Four Common Lockset Types
Locksets are sold in four standard functions, each designed for a different location in your home.
- Passage locksets have no locking mechanism at all. Two handles connect through a spindle so either side can operate the latch freely. These are the standard choice for hallways, closets, and any interior door where privacy isn’t needed.
- Privacy locksets add a push-button or turn-button lock on the interior side, letting you secure a bathroom or bedroom door from inside. The exterior side typically has a small emergency release (a pinhole or slot) so the door can be unlocked from outside in an emergency, but there’s no keyed cylinder.
- Keyed entry locksets include a full cylinder on the exterior side, requiring a key to lock or unlock from outside. Inside, a thumb turn or push button controls the lock without a key. These are designed for exterior doors and any interior door where you need key-controlled access.
- Dummy locksets are purely decorative. They mount to the surface of the door with no latch, no spindle, and no moving parts. You’ll see them on closet doors or the fixed side of double doors where the look of a handle matters but no mechanical function is needed.
Standard Dimensions and Fit
Most residential locksets in North America are built around a few standardized measurements, which means a new lockset will usually drop right into the holes already drilled in your door.
The main bore hole (the large round hole through the face of the door) has a standard diameter of 2-1/8 inches. The latch bore (the smaller hole drilled into the edge of the door where the bolt slides through) measures 1 inch. Standard door thickness for residential locksets is 1-3/4 inches, though some products accommodate doors up to 2 inches thick.
The one measurement that varies is the backset: the distance from the edge of the door to the center of the bore hole. In U.S. homes, this is either 2-3/8 inches or 2-3/4 inches. Most locksets ship with both latch sizes or an adjustable latch, but it’s worth measuring yours before you buy. To check, just measure from the door’s edge to the center of the existing hole.
Security Grades
Locksets sold in the U.S. are tested and rated under the ANSI/BHMA grading system, which assigns one of three grades based on durability and security performance.
Durability testing simulates a lifetime of use, roughly equivalent to 100 years of being opened and closed ten times a day. It also evaluates how well the lockset holds up as seasonal temperature changes cause the door to expand and contract in its frame, and how resistant the finish is to everyday impacts like keys and bags bumping against it.
Security testing measures how the lockset stands up to forced entry: sledgehammer strikes, attempts to physically rip the hardware off the door, and weight loads like a child hanging from a lever. Grade 1 offers the highest performance on both scales and is typical of commercial buildings. Grade 2 is a solid residential choice that balances security with cost. Grade 3 meets minimum standards and is common in light-duty interior applications.
Smart and Electronic Locksets
Electronic locksets replace or supplement the traditional keyed cylinder with digital access methods. Instead of pins and springs, a small motor or actuator physically moves the bolt when it receives an authorized signal from a keypad code, a fingerprint reader, or your phone.
Connectivity is the main variable among smart locksets. Bluetooth models unlock when your phone is within a few feet of the door. Wi-Fi models let you lock and unlock remotely from anywhere with an internet connection. Some use protocols called Z-Wave or Zigbee, which are designed to integrate with broader smart home systems so your lock can talk to your alarm, lights, or voice assistant.
Most smart locksets are designed to fit the same standard bore holes and backsets as mechanical ones, so you can typically swap one in without redrilling your door. They run on batteries (usually AA or CR2 cells) and will alert you when power is running low. Many include a physical key slot as a backup in case the electronics fail.