What it usually means, the likely causes in order, what to safely try first, what a pro charges in Canada, and when to stop and call one.
This guide covers the common cases. Describe your exact problem and get a personalized diagnosis — free to start, with a DIY vs. call-a-pro verdict and a real cost estimate.
Wanting locks rekeyed or a new lock installed is the calm side of locksmith work: a planned security upgrade rather than a malfunction. Rekeying keeps your existing lock hardware but changes the internal pins so a new key works and every old key stops working, which is exactly what most people actually need after moving in, losing a key, or ending a tenancy or relationship. A full installation replaces the hardware itself, which suits a failed lock, a dated look, or a move to a different lock type. Knowing which of the two you need is most of the decision, and it is a pleasant one to make without a deadline.
There is no emergency here, so schedule it at your convenience, with two sensible exceptions. Rekey promptly after moving into a new home, after a key is lost with anything identifying your address, after a break-in, or whenever someone who should no longer have access may still hold a key. In those cases the upgrade is planned but the timing should not drift. Otherwise, bundle the work sensibly: one visit that rekeys every exterior door to a single key is the convenient standard outcome.
The most common trigger. Previous owners, tenants, cleaners, contractors, dog walkers, and former partners may all hold keys you know nothing about. Rekeying resets that unknown list to zero in one visit, without changing a single piece of door hardware, which is why it is the standard first-week job in a new home.
A single lost key with no address attached is a small risk; a lost key alongside identification, or a set of keys missing after a vehicle break-in, is a different calculation. Rekeying the affected doors removes the worry entirely and is usually faster and simpler than replacing locks throughout the house.
When locks are stiff, finishes are failing, or every door in the house takes a different key, replacement or a combined rekey starts to make more sense than preserving the hardware. This is also the natural moment to correct doors that have never latched quite right, since new hardware is fitted and aligned as part of the job.
Many installs are chosen, not forced: a keypad lock for family members who lose keys, a matched set for a renovation, or a higher-grade cylinder for a door you want to strengthen. Framing it as an upgrade lets you choose features calmly, including how you will handle battery changes and backup keys, rather than discovering them during a failure.
| Job size | Typical estimate (CAD) |
|---|---|
| Simple fix — the straightforward version of this repair | $75–$220 |
| Major job — complex, hidden, or replacement-level work | $220–$500 |
Estimates only, calibrated to Greater Toronto Area trade rates and adjusted by region on this site — not a quote. Your exact price depends on the cause, parts, and access. A personalized diagnosis narrows this range using your specific symptom.
Confident homeowners with standard modern locks and the correct rekey kit for that specific lock family sometimes rekey successfully, but pins and springs are small, lock-specific, and unforgiving of a mismatched kit, and a mistake can leave a lock that neither key operates. A locksmith visit is usually the better value for a whole house: every cylinder keyed alike, doors checked for alignment, and old keys verified dead in one appointment. Installation of a like-for-like lock in an existing hole is reasonable DIY for many people; new holes, mortise locks, and misaligned doors belong with a pro.
Rekeying changes the pins inside your existing cylinder so a new key works and old keys do not; the hardware, finish, and door stay exactly as they are. Replacing swaps the hardware itself for a new lock. If your locks are in good condition and your goal is controlling who has access, rekeying achieves it. Replace when the hardware is worn, damaged, or you want a different style or lock type.
Usually, yes, provided the locks use a compatible keyway, which most mainstream residential locks do. A locksmith can rekey compatible cylinders to a single key in one visit. If one door has an incompatible or very old lock, that single lock may need replacing to join the set, which is still far less work than replacing every lock in the house.
Every lock an old key could open: front, back, and side doors, the garage-to-house door, and any other keyed entry. Rekeying only the front door leaves the previous key set working perfectly well at the back. Walk the property and count cylinders before you book, and include any lock you are unsure about in the count you give the locksmith.
For many families, yes: no lost keys, codes that can be changed when access needs change, and no child locked out for want of a key. The trade-offs are batteries to replace, a code that must be managed like a key, and a door that must latch cleanly because the motor cannot force a misaligned bolt. Keep the backup key somewhere you can reach, and treat the install as a lock job first and a gadget second.
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