How to Replace a Door Lock or Deadbolt — Move-In Security Upgrade in 20 Minutes

Learn how to replace a front-door lockset and deadbolt in under 30 minutes with just a screwdriver — no locksmith needed, no drilling required.

Moving into a new home — or just wanting better security — is the perfect reason to swap out your exterior door locks. The good news? Replacing a standard lockset and deadbolt is one of the quickest, most satisfying DIY projects you can tackle. No locksmith, no drilling, no special tools. Just a screwdriver, a matching new lock, and about 20 minutes per door.

Here’s exactly how to do it.

What You’ll Need

• New lockset and deadbolt — must match your door’s backset and crossbore measurements (more on this below)
• #2 Phillips screwdriver (or the bit that matches your lock screws)
• Tape measure or ruler — for checking backset
• A flashlight — for seeing into the door edge

Step 1: Measure Your Door Preparation

Before you buy anything, confirm your door is prepped for a standard cylindrical lock. Two numbers matter:

Backset — the distance from the edge of the door to the center of the lock hole (the big round hole on the door face). Standard backsets are 2⅜" or 2¾". Measure from the door edge straight to the center of the hole.

Crossbore — the diameter of that big round hole. Standard is 2⅛" across.

Most residential exterior doors use one of these two backsets, and virtually every replacement lock sold at a hardware store fits both. If your measurements are anything outside these standards, check the manufacturer’s specs before buying.

Step 2: Remove the Old Lock

All you need is a screwdriver. Here’s the sequence:

1. Unscrew the interior trim plate. On the inside face of the door, you’ll see two screws holding the trim plate (the decorative half of the lockset). Remove them.
2. Pull off both handles. The interior handle comes off once the screws are out. Then pull the exterior handle off from the outside.
3. Unscrew the latch faceplate. Open the door and look at the edge. Two small screws hold the latch plate. Remove them and slide the latch assembly out.
4. Repeat for the deadbolt. Same process — interior trim screws first, then the bolt mechanism from the door edge.

Step 3: Install the New Deadbolt

Start with the deadbolt — it’s the simpler mechanism and sets the alignment for the lockset.

1. Slide the new bolt into the edge hole. The bolt has a beveled side that should face the exterior (the keyed side) and a flat side facing the interior. The bolt should slide smoothly.
2. Screw on the new latch faceplate. Use the screws that came with your lock kit. Most faceplates are rectangular and mortised into the door edge. If the new faceplate is slightly larger than the old one, you may need to chisel the mortise a hair wider — but most replacements are standard size.
3. Attach the exterior keyed assembly. Slide the outside half through the big round hole, aligning the two mounting posts with the bolt housing.
4. Attach the interior assembly. From inside, align the interior half onto the mounting posts and tighten the mounting screws. Test the key — it should turn smoothly and extend/retract the bolt.

Step 4: Install the New Lockset (Handleset)

With the deadbolt in place, the lockset goes in the same way:

1. Insert the latch. Slide a new latch into the edge hole below the deadbolt, bevel facing the exterior.
2. Attach the exterior handle. Pass the outside handle through the crossbore hole.
3. Attach the interior handle. Line up the interior handle’s mounting posts with the latch, and tighten the screws.
4. Test operation. Open and close the door with the handle. The latch should engage the strike plate smoothly. If it sticks or rubs, you may need to adjust the strike plate position.

Step 5: Test Everything Before You Lock Up

Before declaring victory, run through this checklist:

• Key operation: Insert and turn the key in the deadbolt from both sides. It should work smoothly without forcing.
• Latch operation: Close the door and turn the thumb latch inside. The bolt should extend fully into the strike plate opening.
• Handle operation: Pull the door shut and turn the handle. The latch should retract easily and the door should open.
• Door alignment: After installing, the door should fit in the frame as it did before. If the latch doesn’t engage the strike plate cleanly, loosen the strike plate screws slightly and tap it a few millimeters in the direction it needs to go, then retighten.

When to Call a Locksmith

Most lock replacements are straightforward, but call a pro if:

• Your door is metal or fiberglass with no pre-drilled holes. Installing a deadbolt in a solid-core door that was never prepped for one requires a hole saw, a jig, and precision — one mistake and the door is ruined.
• The deadbolt doesn’t align with the strike plate. If the bolt misses the strike plate opening by more than ⅛" after minor strike plate adjustment, the frame may have shifted. A locksmith or carpenter can reposition or enlarge the strike plate.
• You need to re-key multiple locks to one key. If you want all exterior doors to use the same key, you can buy a re-keying kit for about $15 per lock and do it yourself in 10 minutes — or have a locksmith do the whole house in under an hour.

What homeowners actually search:

• “how to change a door lock without original key”
• “replace door lock backset 2 3 8 vs 2 3 4”
• “can I install a deadbolt myself”
• “how to rekey a lock rather than replace”

Pro Tips for a Clean Installation

Test the bolt alignment before tightening everything. Slide the deadbolt latch into the door edge, loosely thread the faceplate screws, then test the key mechanism. If the bolt sticks, shift the plate a millimeter or two and retest. Tighten only when the bolt moves freely.

Watch the handing direction. Exterior locks are handed — meaning the thumb latch and key orientation depend on whether the door opens from the left or right. Most modern locksets are reversible, but check the instructions. Installing a left-handed lock on a right-handed door puts the thumb latch on the wrong side.

Don’t overtighten. Handles and deadbolts work with smooth rotation. If you crank down the mounting screws with all your strength, you can bind the mechanism. Tighten until snug, then back off a quarter turn if the key feels stiff.

Why This Matters

Your exterior door locks are the physical barrier between your family and anyone who shouldn’t be inside. Replacing them — at minimum when you move into a new home — means you control every key. You don’t know who the previous owner gave keys to, or how many copies exist. A $35 deadbolt and 20 minutes of your time is the cheapest home security upgrade you can make, and one of the most effective.

This post targets high-intent search queries from new homeowners (people who just moved and need to change locks immediately) and security-conscious renters. The “no locksmith needed” framing addresses the #1 search objection. Include strong internal links to the sticking exterior door fix post for readers who discover alignment issues during their lock swap.