Replacing a door lock or deadbolt takes about 15 minutes and is one of the easiest ways to improve home security. You should change locks anytime you move into a new home, lose a key, or the lock becomes difficult to operate.
STEP 1: Measure Your Existing Lock
Measure the backset — the distance from the edge of the door to the center of the lock hole. Standard backsets are 2-3/8 inches or 2-3/4 inches. Buy a replacement that matches. Also check your door thickness — most interior and exterior doors are 1-3/8 or 1-3/4 inches thick.
STEP 2: Remove the Old Lock
Once you have that handled, unscrew the interior mounting screws to separate the interior and exterior halves. Pull both sides apart and remove the latch bolt from the edge of the door. If replacing a deadbolt, remove the thumb turn on the inside and the key cylinder on the outside the same way.
STEP 3: Install the New Latch or Bolt
Now that the first pieces are in place, insert the new latch bolt into the hole on the edge of the door with the angled face of the latch pointing toward the door frame (the direction the door closes). Screw the latch plate flush with the door edge.
STEP 4: Attach the Exterior and Interior Assemblies
With the core work behind you, insert the exterior half through the latch, aligning the tailpiece or connecting bar. Press the interior half against the door and tighten the mounting screws evenly — alternate between screws to keep it centered. Do not overtighten.
STEP 5: Test and Adjust the Strike Plate
The last piece of the puzzle is close the door and test the lock several times with the key and from inside. If the bolt does not align with the strike plate hole in the frame, remove the old strike plate and install the new one included with the lock. Use a chisel to enlarge the mortise if needed.
PRO TIPS
Q: How do I make my door locks harder to kick in?
A: Always replace the strike plate with a heavy-duty version that has 3-inch screws reaching into the wall stud — not just the door frame. The strike plate is the weakest point in most doors and a $5 reinforced plate with long screws makes a door dramatically harder to kick in.
Q: Should all my exterior doors be keyed alike?
A: If you have multiple exterior doors, buy locks that are keyed alike — one key opens all of them. Most major lock brands sell keyed-alike sets or your hardware store can re-key locks to match for a small fee.
Q: What ANSI grade deadbolt is best for a house?
A: Choose a deadbolt with at least an ANSI Grade 2 rating for residential use. Grade 3 locks are builder-grade and offer minimal security. Grade 1 is commercial-grade and the most secure, but Grade 2 is the sweet spot for most homes.
SUPPLIES NEEDED
Replacement lock or deadbolt set
Phillips screwdriver
Tape measure
Chisel (if adjusting the mortise)
Hammer
Pencil
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