Few things are more frustrating than a lock that won’t turn smoothly or makes you jiggle the key just to get inside. It’s inconvenient, it’s a security risk, and it’s usually a sign the lock needs replacing.
Here’s everything you need to know: how to prep, measure, and install a door lock step by step.
Key Notes
- Measure backset (2⅜ or 2¾ inches) and door thickness before buying replacement locks.
- Remove old lock components, install the new latch first, then attach the handles and strike plate.
- Test thoroughly by operating the lock multiple times and checking the bolt extension alignment.
- DIY takes 45-60 minutes; professional installation recommended for smart or high-security locks.
Tools & Materials You’ll Need
Before you get started, gather the right gear. Here’s a typical toolkit for changing a standard lock:
- Screwdrivers (Phillips and flathead)
- Tape measure
- Drill and bits (optional but useful for adjustments)
- Chisel and hammer (for strike plate or latch adjustments)
- Pencil or marker (for marking measurements)
- Lubricant (graphite or silicone-based)
- New lockset (double-check compatibility with your door thickness and dimensions)
Having everything on hand before you start saves you from mid-project trips to the hardware store.
Measuring for a New Lock
One of the most common mistakes is buying a lock that simply doesn’t fit.
To avoid this:
- Measure the backset: distance from the door edge to the lock’s center (typically 2 ⅜ or 2 ¾ inches).
- Measure the door thickness: most locks fit 1 ⅜ to 1 ¾ inches, but check.
- For cylinder locks, measure the cylinder length (and whether it’s equal or offset).
- Note any specific lock type measurements (mortice, rim, multipoint) as each varies.
- Double-check before buying, and snap a quick photo of the existing lock for comparison.
Step-by-Step Guide: How to Change a Door Lock
Step 1: Gather tools and new lockset
Lay everything out before starting.
Step 2: Remove the old lock
Unscrew and remove the interior knob/handle, then pull off both sides. Unscrew and remove the latch mechanism from the door edge.
Finally, remove the strike plate from the frame.
Step 3: Prepare the door
Check dimensions and clean up the mortise cavity. Use a chisel if the new latch plate needs a slightly larger recess.
Step 4: Install the new latch
Slide it into the edge of the door, ensuring the beveled side faces the door jamb. Screw it in place.
Step 5: Install knobs or handles
Insert the spindle through the latch and attach both knobs/handles. Tighten screws firmly but don’t overtighten.
Step 6: Replace the strike plate
Line up with the latch and secure it flush to the frame.
Step 7: Test the lock
Check operation with the door open and closed. Ensure smooth locking/unlocking.
Step 8: Final adjustments
Adjust strike plate if the latch doesn’t align. Tighten any loose screws. Lubricate if necessary.
Is Your Lock Trouble A Door Problem?
Common Mistakes to Avoid
Plenty of DIYers run into the same pitfalls:
- Installing the lock upside down
- Misaligning the strike plate, causing jamming
- Choosing cheap, poor-quality locks that don’t last
- Ignoring weather resistance on exterior doors
- Over-tightening screws and warping parts
- Skipping lubrication or ongoing maintenance
Troubleshooting & Adjustments
If things aren’t working perfectly after installation:
- Adjust the strike plate by loosening and shifting it slightly.
- Shim or tighten door hinges if the door has sagged.
- Lubricate stiff mechanisms.
- If the lock feels wobbly, check and tighten all screws.
Testing Your New Lock for Security
Don’t just walk away after installation – test thoroughly:
- Operate the lock several times from both sides
- Make sure the bolt fully extends into the strike plate
- Confirm the door closes smoothly without forcing
- Check that screws and plates are secure
- For smart locks, test all functions: keypad, app, battery backup
DIY vs Professional: Which Is Right for You?
- DIY: Expect 45–60 minutes if you’re handy. It saves money but comes with a learning curve.
- Professional locksmith: Usually done in 20–30 minutes with precision and proper tools. Especially worth it for high-security or electronic locks, or if your door needs adjustments.
Frequently Asked Questions
How often should you change your door locks?
There’s no fixed timeline, but many homeowners replace locks every 7–10 years or sooner if they’re worn, after moving into a new place, or when upgrading to higher security options.
Can I change a door lock without changing the keys?
Yes, some lock brands offer interchangeable cores or allow you to buy a new lock keyed alike to your existing keys. Otherwise, rekeying is the way to keep your current key.
What’s the difference between a deadbolt and a knob lock?
A knob lock is built into the door handle and is convenient but less secure. A deadbolt extends deeper into the frame, making it far more resistant to forced entry. Most exterior doors use both for better security.
Do new locks come with all the parts I need?
Typically yes – new locksets include screws, strike plates, and keys. But it’s smart to double-check packaging and compare with your existing door setup before you start the swap.
Conclusion
Changing a lock isn’t complicated, but it does demand care and patience.
Knowing how to change a door lock means choosing the right type of lock, preparing the tools, and following each step carefully – from removing the old hardware to testing the new installation.
Avoiding common mistakes, checking alignment, and taking time to test the lock can make the difference between a quick fix and ongoing frustration.
If your lock issues point to a bigger problem – like a failing door, poor alignment, or outdated hardware – we can help. Book a free appointment for expert installation, reliable repairs, and tailored recommendations that keep your property secure and looking its best.
