How to Replace a Door Lock?

Replacing a door lock is a straightforward DIY job that usually takes 15–30 minutes with just a screwdriver. This covers a standard knob/lever lock and deadbolt.

What you need:

• A new lock set (measure first — see below)
• A Phillips screwdriver
• A tape measure
• Optionally a chisel, if the new plate doesn't match the old cutout

Measure before buying:

• Backset: the distance from the door edge to the center of the hole — almost always 2 3/8" or 2 3/4".
• Bore hole diameter: the big hole, typically 2 1/8".
• Door thickness: usually 1 3/8" to 1 3/4".

Step-by-step:

1. Remove the old lock. Unscrew the two screws on the interior side of the knob/deadbolt, then pull both halves apart and off the door.
2. Remove the latch plate. Unscrew the small plate on the edge of the door and slide the latch/bolt mechanism out of its hole.
3. Remove the strike plate on the door frame if you're replacing it (most new lock sets include a fresh one).
4. Install the new latch. Slide the new latch into the edge hole with the angled side facing the direction the door closes, then screw its plate in place.
5. Fit the new lock. Insert the exterior half so its stems/spindle pass through the latch mechanism, then hold the interior half against it, line up the screw holes, and tighten the screws evenly. Don't overtighten.
6. Install the new strike plate on the door frame, screwing it into the existing holes.
7. Test it. Open and close the door several times, and check the key and the lock/unlock action. If the latch doesn't catch cleanly, loosen the strike plate and adjust it slightly.

Tips: Keep the screws you remove — they're easy to lose. If the new strike plate is a different shape, you may need to chisel the frame recess slightly. For keyed-alike convenience, buy locks from the same brand and series so one key works everywhere.