When a lock stops working or you've lost keys, you face a quick decision: replace the entire lock or rekey the existing one? Both solve your problem, but the cost difference can be substantial, and the right choice depends on your lock's condition, security needs, and budget.
What's the Difference?
Rekeying means a locksmith disassembles your existing lock and rearranges the internal pins so your old keys no longer work. You get a new key set that operates the same physical lock. The lock body stays in place on your door.
Lock replacement removes the entire lock mechanism and installs a new one. Your door hardware is completely swapped out, and you receive new keys for the fresh lock.
Cost Comparison: Real Numbers
For a standard residential deadbolt:
- Rekeying: $50–$150 per lock, typically at the lower end ($75–$100) for a single lock on the same key system
- Lock replacement: $150–$300+ per lock, depending on the lock quality and brand
If you're rekeying multiple locks to match one key (common when moving into a new home), expect $200–$400 total for 3–4 locks. Replacing those same locks runs $500–$900 or more.
Service call fees also apply. Some locksmiths charge $50–$100 just to show up; others roll this into the final bill if you proceed with work.
When Rekeying Makes Sense
Rekey your existing locks if:
- The lock mechanism works smoothly with no jamming or grinding sounds
- You've simply lost keys or want to invalidate old keys (tenant move-out scenario)
- Your door hardware is relatively new (last 5–10 years)
- You're on a tight budget
- Multiple locks use the same key system already, or you want them to
A typical homeowner moving into a resale house often chooses rekeying for 3–5 entry locks at once, spending $300–$500 total instead of $700–$1,500 for replacements.
When Replacement Is the Better Choice
Choose lock replacement if:
- The lock is visibly damaged, rusted, or the cylinder is cracked
- The lock is 15+ years old and losing its holding strength
- You want a higher security grade (upgrade from a basic pin-tumbler to a high-security or smart lock)
- The lock frequently sticks or requires extra pressure to turn
- You're upgrading to a keyless entry or smart lock system (requires new hardware entirely)
- The existing lock is an unusual vintage type that a locksmith won't rekey safely
A corroded outdoor deadbolt or a lock that grinds when turned is a sign the pins are wearing out—rekeying won't restore smooth operation.
Labor Time and Installation
- Rekeying: 15–30 minutes per lock; same-day service is standard
- Replacement: 20–45 minutes per lock; may require door adjustment if the new lock doesn't align perfectly with existing holes
Both typically finish within a single appointment, though weekend or emergency calls (nights, holidays) add 25–100% to the bill.
Hidden Costs to Watch For
| Issue | Cost Impact | |-------|------------| | Door frame damage (rotted wood, enlarged holes) | +$100–$500 for frame repair before new lock installs | | Specialty lock types (euro cylinders, mortise locks) | Rekeying may be impossible; replacement necessary | | Smart lock installation | +$200–$400 for smart lock hardware vs. standard deadbolt | | Multiple properties (landlord scenario) | Bulk rekeying discounts possible; ask locksmith for multi-unit pricing |
Getting Accurate Quotes
Call 2–3 licensed residential locksmiths and ask them to:
- Confirm whether they recommend rekeying or replacement based on lock age and condition
- Quote both options (you'll see the cost gap clearly)
- Specify what's included (service call, new keys, key copies)
- Mention if they offer same-day service or guarantees on their work
Avoid locksmiths who refuse to assess your lock first or push replacement without explanation. You want Mercoly helps you compare and find trusted Residential Locksmiths providers in one place, making it easier to verify credentials and reviews before booking.
Frequently Asked Questions
Q: Can a locksmith rekey a lock with a broken key still stuck inside? A: No—the locksmith must first remove or drill out the broken key fragment before the lock can be rekeyed. This adds $50–$100 to the cost and may damage the cylinder, making replacement the safer option.
Q: Is it cheaper to rekey all locks to one master key when I move in? A: Yes. Rekeying 4–5 locks to match one master key typically costs $250–$350 total, versus $600–$1,200 for replacing them all.
Q: Do smart locks require a professional locksmith to install? A: It depends on the model—some install as a drop-in replacement for existing deadbolts, but electronic smart locks often need a locksmith to ensure proper alignment, weatherproofing, and backup mechanical key function.
Start by calling local licensed locksmiths today to compare both options for your specific locks and doors.