Doors, locks & garage doors

Deadbolt won't lock or extend fully

A deadbolt that won't fully extend is most often being blocked by a misaligned strike plate rather than a broken lock mechanism.

Difficulty
Easy
Time
20–40 minutes
DIY cost
$5–$15
Pro cost
$80–$150

Symptoms

  • Thumb-turn or key turns partway then stops
  • Bolt doesn't fully extend into the frame
  • Door has to be lifted, pulled, or pushed for the bolt to engage

Likely causes

  • CommonStrike plate hole misaligned with the boltHouse settling or a sagging door commonly shifts this alignment over time.
  • CommonDoor not sitting square in the frame when closedA warped or sagging door changes where the bolt lines up.
  • PossibleDebris or paint buildup in the strike plate holeDirt or paint can block the bolt from fully seating.
  • PossibleBent bolt or worn lock mechanismPhysical damage to the bolt itself will prevent smooth operation.

What to do

  1. Close the door and try to lock it, noting exactly where the bolt stops.
  2. Check the strike plate hole for paint, dirt, or debris and clean it out.
  3. Apply lipstick or chalk to the end of the bolt, close the door, and try locking to see where it marks the strike plate.
  4. Adjust or enlarge the strike plate hole based on the mark, or reposition the plate if needed.
  5. Check hinge screws and tighten or replace any that are loose to fix a sagging door.
  6. Lubricate the bolt and strike plate with dry lubricant once alignment is corrected.

Tools and parts

  • Screwdriver
  • Metal file
  • Dry lock lubricant
Replacement strike plateSearch: “door strike plate”

When to call a pro

Call a locksmith or handyman if adjusting the strike plate doesn't fix it, or if the bolt itself appears bent or damaged.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.