What happens when you change a car key
Changing a car key usually means one of two things: replacing the battery in a key fob that still works but no longer locks or unlocks your car, or getting a new key made because yours is lost, broken, or worn out. Battery replacement is something you can often do yourself in under five minutes. Getting a replacement key requires a trip to a dealership, a locksmith, or sometimes an auto parts store, and the cost and time depend on what kind of key your car uses.
The process is straightforward either way, but the route you take and what you pay depends on whether your key is a straightforward mechanical key, a key fob with a replaceable battery, or a smart key that needs programming to your specific vehicle.
Key Takeaways
- Most key fob batteries cost between $3 and $15 and can be replaced at home by prying open the fob and swapping in a new battery of the same type.
- Dealerships charge the most for replacement keys but can make any key your car needs, including smart keys that require programming.
- Locksmiths and auto parts stores are usually cheaper than dealerships and can make standard keys and some fobs on the spot.
- You will need proof of ownership and a government ID to get a replacement key from most places.
- Smart keys and transponder keys cost more to replace than mechanical keys because they require programming or special equipment.
Replacing a key fob battery yourself
If your key fob stops working but you still have the physical fob in your hand, the battery is usually dead and can be replaced without leaving home. Look for a small slot or seam around the edge of the fob where the two halves meet. Use a flat tool — a coin, a butter knife, or a plastic pry tool — to gently separate the two halves.
Once the fob is open, note the size and type of the battery. It will be stamped with a code like CR2032, CR2025, or similar. Take a photo or write down the code, then buy a replacement battery of the exact same type from a pharmacy, grocery store, or dollar store. The cost is usually $3 to $8. Slide the new battery in, making sure the positive side faces the same direction as the old one, then snap the fob back together and test it.
If the fob still does not work after a new battery, the problem is not the battery — the fob itself may be damaged or the car's receiver may need attention. At that point, you will need a replacement key.
Getting a replacement key from a dealership
The dealership is the most reliable place to get a replacement key, especially if your car uses a smart key or a transponder key that requires programming. Dealerships have the equipment and software to program new keys to your specific vehicle, and they can make any type of key your car needs.
Bring your government ID and proof of ownership — your registration or title. The dealership will verify that you own the car, then make the key and program it. This usually takes 30 minutes to an hour, though some dealerships may need to order the key and have you return later. Cost varies widely by car make and model, but expect to pay $150 to $400 for a smart key or transponder key, and $50 to $150 for a basic mechanical key.
Dealerships are open during business hours only, and you may need an appointment. If you need a key outside normal hours, a locksmith is your only option.
Getting a replacement key from a locksmith
A locksmith can make most types of car keys and is usually faster and cheaper than a dealership. Locksmiths can cut mechanical keys on the spot, and many can also program transponder keys and fobs if they have the right equipment. Call ahead to confirm they can handle your car's key type before you go.
Bring your ID and proof of ownership. The locksmith will verify ownership, cut the key, and program it if needed. A mechanical key usually takes 15 to 30 minutes and costs $10 to $50. A transponder key or fob takes longer and costs $75 to $250 depending on the car and the locksmith's equipment. Many locksmiths offer emergency service and can come to you if your car is locked and you have no key.
Not all locksmiths have the equipment to program every type of key, so ask specifically whether they can program keys for your car's make and model. If they cannot, they can usually cut the key but you will still need to go to a dealership for programming.
Getting a replacement key from an auto parts store
Some auto parts stores, including national chains, offer key cutting and programming services. They can usually cut mechanical keys and some basic fobs, and a few locations have the equipment to program transponder keys. Call your local store to ask what services they offer and whether they can handle your car's key type.
Bring your ID and proof of ownership. The process is similar to a locksmith: they will verify ownership, cut the key, and program it if they have the capability. A mechanical key costs $5 to $30 and takes 15 minutes. A fob or transponder key costs $50 to $150 and takes 30 minutes to an hour. Auto parts stores are usually open longer hours than dealerships, including weekends, which can be convenient if you need a key outside normal business hours.
The downside is that not all locations offer all services, and some may not be able to program keys for less common car makes. Call ahead to confirm before you go.
What to do if you have lost your only key
If you have lost your only key and cannot get into your car, a locksmith is usually your fastest option. Many locksmiths offer emergency service and can come to your location and make a key on the spot, even if it is nights or weekends. You will still need to show proof of ownership — your registration, title, or insurance card — so have that ready before you call.
If you cannot reach a locksmith, call your dealership. Some dealerships have emergency key services and can make a key if you can prove ownership. If your car is locked and you need to get inside, a locksmith can also unlock the door without damaging it, though this is a separate service and costs extra.
If your car is financed or leased, your lender or leasing company may have a process for emergency key replacement. Check your paperwork or call the customer service number on your loan or lease agreement.
Understanding different key types and their costs
The type of key your car uses determines where you can get a replacement and how much it will cost. A mechanical key is a straightforward metal key with no electronics — older cars and some newer basic models still use them. These are the cheapest to replace, usually $10 to $50, and any locksmith or auto parts store can cut one.
A transponder key has a small computer chip inside that communicates with your car's ignition system. If the chip is not programmed to your car, the engine will not start even if the key fits. Transponder keys cost $75 to $200 to replace because they require programming equipment. Dealerships, most locksmiths, and some auto parts stores can program them.
A smart key or keyless entry fob lets you lock and unlock your car from a distance and sometimes start the engine with a button. Smart keys are the most expensive to replace, usually $150 to $400, because they require specialized programming and equipment. Only dealerships and high-end locksmiths can program them, and you may need to order the key rather than get it on the spot.
Frequently Asked Questions
Can I program a replacement key myself?
For most cars, no — programming requires specialized equipment that only dealerships and locksmiths have. Some older cars have a procedure you can do at home by turning the key in the ignition a certain number of times, but this is rare. Check your owner's manual or call your dealership to ask whether your car supports self-programming.
What if I do not have my registration or title?
You will need some form of proof of ownership. A driver's license with your name and address, an insurance card, or a loan or lease agreement can work. Call ahead and ask what documents the dealership or locksmith will accept before you go.
How long does it take to get a replacement key?
A mechanical key takes 15 to 30 minutes at a locksmith or auto parts store. A transponder key takes 30 minutes to an hour. A smart key may take an hour or more, and some dealerships may need to order it and have you return the next day. Emergency locksmith services may take longer if they have to travel to you.
Is it cheaper to get a key from a locksmith or a dealership?
Locksmiths are usually 20 to 40 percent cheaper than dealerships for the same key type. However, not all locksmiths have the equipment to program every type of key, so you may end up at a dealership anyway. Get quotes from both before you decide.
What should I do if my key fob is damaged but the battery is fine?
If the fob is cracked, the buttons do not work, or it does not respond after a new battery, the fob itself is damaged and needs to be replaced. You can get a replacement fob from a dealership, locksmith, or auto parts store using the same process as getting a new key.