Why You Need a Spare Car Key Before You Lose the Only One
Why get a spare car key now? Because copying a key that works is a simpler job than replacing a key that is gone. With a working key in hand, a locksmith can read its cuts and add a new key to the car in one short visit. With every key lost, a new key has to be made from scratch, decoded from the lock or looked up by code, then fully programmed, often while the car sits stranded. Almost every type of car key, from plain metal to push-to-start smart keys, can be duplicated.
A spare is the simplest protection against your worst day with the car. Here is how each key type gets copied, where a spare belongs and where it does not, and what to have ready when you get one made.
Copy versus replace: why timing matters
A duplicate starts from something that works. The locksmith can trace or decode the cuts from your key, and on chip keys the car is usually ready to accept an additional key while a working one is present. On some vehicles, the chip can even be cloned from your original.
A replacement for lost keys starts from nothing. The cuts have to be decoded from a door lock or looked up by code, the right blank has to be matched, and the new key has to be programmed into a car you may not even be able to open. On some models, adding a key without a working one is a longer, more involved procedure, and a few send you to the dealer. Our guide on lost car keys covers that path. A spare is how you avoid needing it.
There is a practical side too. Lose one key out of two and you still drive the car, then have the lost key erased when it suits you. Lose your only key and every option starts with the car stuck where it is.
Which keys can be duplicated, and how
- Cut-only metal keys. Older cars without a chip. The key is copied on a key machine or cut to the factory code. Fast and simple.
- Transponder keys. The blade is cut, then the chip is either cloned from your key or programmed to the car as a new key. Our guide to transponder keys explains the difference.
- Remote head and flip keys. Blade, chip, and remote buttons share one head. The blade is cut, the chip is programmed, and the remote functions are programmed too, sometimes as a separate step.
- Smart keys. Push-to-start proximity fobs are programmed to the car with diagnostic equipment, and the emergency blade hidden inside is cut to your door lock. Do not skip the blade. It is how you get in when the fob battery dies.
- Laser-cut keys. These thick blades with a groove milled along the side, common on newer cars, need a specific cutting machine that many key counters do not have.
A few models let an owner add a key with two existing working keys and a sequence from the manual. Most cars built in the last fifteen years, though, need diagnostic equipment. And if your daily key is worn, have the spare cut to the factory code rather than copied, because a copy of a worn key inherits every rounded cut.
Valet keys: useful, but know their limits
Some cars, mostly older ones, came from the factory with a valet key. It opens the driver door and starts the engine, but on many models it will not open the trunk or glove box. The idea is that you can hand it to a parking attendant without handing over whatever is locked away.
Two things to know. First, a valet key still starts the car, so treat it as a real key and never leave it in the glove box or anywhere in the car. Second, it makes a fair emergency backup, but it is not a full spare. If it is the only backup you have, consider adding a full duplicate. On many newer cars, valet mode is a setting rather than a separate key, and your owner's manual explains how it works on yours.
Where to keep a spare, and where not to
A spare only helps if you can reach it when the main key is gone, and nobody else can. Good places:
- A consistent spot at home that everyone in the household knows.
- With a trusted person nearby, for the day you lose a key away from home.
- In the household go-bag, if you live in fire-prone hills, so anyone at home can move the car during an evacuation.
Bad places:
- Inside the car, glove box included. A spare in the car is a key for a thief.
- A magnetic box under the bumper. It is the first place anyone looks.
- On the same ring as the main key. Then it is not a spare, just a second key you lose at the same moment.
Smart key spares need one more thought. Thieves can relay a fob's signal from inside a house to a car in the driveway. Keep fobs away from the front door and the walls nearest the car, or in a signal-blocking pouch, and check whether your fob or car offers a sleep mode.
What to bring to get a spare made
- Your working key, ideally every key you have. Some programming procedures reset all keys at once, and a key left out may stop working.
- The car, for any key with a chip or remote. With a mobile locksmith that part is easy, because the van comes to where the car is parked.
- Registration and photo ID that match, so the person making the key knows it is yours to copy.
- Year, make, and model, given on the phone, so the right blank and remote are on the van.
Our car key cutting and duplication service handles everything from cut-only keys to smart keys across Ventura County and San Diego County, with a flat quote on the phone before any work starts.
Test the spare, then keep testing it
Before the locksmith leaves, try the spare at every job it should do: lock and unlock the doors by hand and by remote, open the trunk, and start the engine. If it is a smart key, try the emergency blade in the door lock as well.
Then set a reminder. A spare fob in a drawer still drains its battery slowly, and a dead spare fails you on exactly the day you reach for it. Every few months, try it on the car, and change its coin cell when you change your main one. Our guide to key fob battery replacement walks through that job.
Frequently Asked Questions
Is it cheaper to copy a car key or replace a lost one?
Copying a working key is almost always less work, and less work usually means a smaller bill. The locksmith reads the cuts from your key and adds the new one to the car, often in a short visit. Replacing lost keys means decoding the lock or looking up the code, programming from scratch, and sometimes a tow for dealer-only models. Either way, ask for a flat quote first.
Can a hardware store copy my car key?
Sometimes, for older cut-only keys and some basic chip keys that can be cloned. Many key counters cannot cut laser-cut blades, and most cannot program remote head keys or smart keys to the car. A copy that unlocks the door but will not start the engine usually means the chip was never programmed. For anything with buttons or a chip, an automotive locksmith is the more direct route.
Will my spare stop working if I lose the other key?
Not on its own. A spare keeps working until someone changes the car's key memory. If you lose a key, it is smart to have the lost one erased, and when that happens the locksmith programs your remaining keys back in during the same visit. Bring every key you still have so none of the good ones get left out of the car's memory.
Does a valet key count as a spare?
It can get you home, because on cars that came with one it unlocks the driver door and starts the engine. On many models it will not open the trunk or glove box, so it is a limited backup rather than a full one. If the valet key is your only spare, keep it somewhere safe outside the car and think about adding a full duplicate.
How many keys should I have for my car?
Two working keys is the minimum worth having: one you carry and one kept somewhere safe. Households with more than one regular driver often keep three, so everyone has a key and a spare still sits at home. Some cars also make adding a key easier when you already have two working ones, which is one more reason not to let it drop to one.
Down to one key? Call or text with your year, make, and model. We come to the car, make and test the spare on the spot, and quote it flat before any work starts.
Ventura County (805) 765-3717San Diego (619) 768-2745We serve Ventura County including Oxnard, Ventura, Thousand Oaks, Simi Valley, Camarillo, and San Diego County including San Diego, Chula Vista, Oceanside, Carlsbad, Escondido.
