The short answer: you need duplication if you still have at least one working key and simply want another, and you need replacement if you have no working key left — because it was lost, stolen or broken beyond use. Duplication copies something that already exists; replacement builds a new key from the vehicle itself. That difference affects how the job is done, how long it takes and what it costs.

Not sure which applies to you? Call (613) 707-4884 with your make, model and year.

What Car Key Duplication Means

Duplication starts with a key that already starts your car. The new key is made from it in two parts:

  • The blade. The cuts on your existing key are traced or decoded and reproduced on a new blank. Older vehicles use edge-cut blades; many newer ones use high-security "laser-cut" or sidewinder blades that need a specialised cutting machine.
  • The electronics. Most vehicles built since the late 1990s have a transponder chip in the key that the engine immobilizer must recognise. Depending on the chip, a duplicate is either cloned from your existing key or added to the car's memory as an extra key with programming equipment.

A plain metal key with no chip (common on older vehicles and some trailers or equipment) is a simple cut-and-go copy. A key with a transponder or a remote needs the electronic step as well — a blade that only turns the ignition will not start an immobilized engine.

What Car Key Replacement Means

Replacement is needed when there is nothing to copy. Instead of reading an existing key, the locksmith or dealer works from the vehicle:

  1. Proof of ownership is checked — registration and photo ID that match.
  2. The blade is generated from the vehicle's key code or by decoding a door or ignition lock.
  3. The new key is programmed to the immobilizer, and remote or proximity functions are set up if the vehicle has them.
  4. Missing keys are dealt with. On many vehicles, lost keys can be erased from the car's memory so they no longer start it.

Manufacturers treat lost keys seriously. Mazda's owner's manual, for example, notes that when a key is lost the electronic codes of the immobilizer and the remaining keys are reset, and asks owners to bring all remaining keys for that reset. Other brands follow similar logic, so gather every key you still have before the appointment.

Side-by-Side: Which One Fits Your Situation?

  • You have one key and want a backup — duplication.
  • A household member needs their own key — duplication.
  • Your only key is lost or stolen — replacement, ideally with the old key erased from the car.
  • The blade snapped but the head still works electronically — often a new blade or shell can be fitted and the chip transferred, which sits between the two.
  • The remote buttons stopped working but the car still starts — usually neither; check the battery first, then look at fob repair or programming.

Why Duplication Is Usually Simpler and Cheaper

With a working key in hand, the blade cuts are already known and, on many vehicles, adding a key is a routine procedure. Replacement involves extra steps: decoding the lock or retrieving the key code, verifying ownership more carefully, and sometimes resetting the immobilizer. The main cost factors in either case are the key type (plain, transponder, remote-head or smart key), the blade style, whether the vehicle requires special access to add keys, and whether the work happens in a shop or on site.

For a deeper look at the chip side of things, see how transponder car keys work. If you are already down to zero keys, our guide on lost car keys with no spare walks through the next steps.

The Practical Takeaway: Copy Before You Lose It

The best time to duplicate a car key is while you still have one that works. A spare made today is a straightforward job; the same key made after the original is gone becomes a replacement, with more steps and more downtime. Keep the spare somewhere secure at home — not in the car.

Next Step

If you have a working key and want a backup, see our spare key duplication service. If you have no working key, or you are unsure whether your key can be copied, call (613) 707-4884 and have your vehicle's make, model and year ready.