Where to get a car key battery replaced
The fastest place to replace a car key battery is usually your car's dealership, a local locksmith, or a big-box retailer like Best Buy or Walmart that has a battery or electronics section. Dealerships typically charge $50 to $150 for the service, locksmiths charge $20 to $75, and retailers charge $10 to $30. The trade-off is speed versus cost: dealerships often have your exact key type in stock and can do it while you wait, but locksmiths and retailers are usually cheaper and may be closer to your home.
Many people don't realise they can replace the battery themselves in under five minutes. If your key fob has a visible seam or slot, you can usually pry it open with a coin or flathead screwdriver, swap out the old battery for a new one of the same type (usually CR2032, CR2025, or similar), and snap it back together. The battery itself costs $3 to $8 at any pharmacy, supermarket, or hardware store.
Before you go anywhere, check your owner's manual or search your car's make and model online to confirm which battery type your key uses. This takes two minutes and saves you from buying the wrong size.
Key Takeaways
- You can replace most car key batteries yourself in minutes using a coin to open the fob and a replacement battery from any pharmacy or supermarket.
- Dealerships charge $50 to $150 but have your exact key type and can usually finish while you wait.
- Locksmiths and big-box retailers charge $10 to $75 and are often faster to reach than a dealership.
- The battery type (CR2032, CR2025, etc.) is printed in your owner's manual or visible on the old battery once you open the fob.
How to tell your key battery is dying
A dying key fob battery shows itself in a few clear ways. The most obvious sign is that you have to press the button harder or multiple times to lock or unlock your car, or the button works only when you hold it close to the vehicle. You might also notice the range has shrunk—you used to unlock your car from across a parking lot, but now you have to be within a few feet.
Some key fobs have an LED light that dims or stops working when the battery is low. If your fob has one and the light is noticeably dimmer than it used to be, the battery is on its way out. A completely dead battery means the fob won't work at all, even when pressed hard or held right against the car.
The good news is that a dying battery is not an emergency. Your car's physical key is still inside the fob—you can always unlock the door manually and start the engine with the key blade if the fob stops working entirely. This gives you time to replace the battery without rushing.
What type of battery your key fob uses
Most car key fobs use a coin-cell battery, which is a small, flat, round battery about the size of a dime or nickel. The most common types are CR2032 (used in roughly 70% of key fobs), CR2025, CR2016, and CR1632. Some luxury cars and newer models use slightly different sizes, but coin cells are by far the standard.
The battery type is usually printed on the old battery itself once you open the fob, or listed in your owner's manual under "key fob" or "remote control." You can also search "[your car make and model] key fob battery" online and find the answer in seconds. Never guess—buying the wrong size wastes money and won't work.
Coin-cell batteries are sold everywhere: pharmacies, supermarkets, hardware stores, petrol stations, and online retailers. A single battery costs $3 to $8. Some places sell multipacks if you want spares for other devices like watches or calculators.
Replacing the battery yourself: step by step
Open your key fob by finding the seam or slot where the two halves meet. This is usually on the side or back. Insert a coin (a penny or dime works well) or a flathead screwdriver into the slot and gently twist or pry until the fob pops open. Be gentle—you don't want to crack the plastic or damage the circuit board inside.
Once open, you'll see the old battery sitting in a small metal holder or clip. Note which side is facing up (the flat side or the raised side with a plus sign). Remove the old battery by gently prying it out with your fingernail or the edge of a coin. If it's stuck, a tiny bit of gentle wiggling usually frees it.
Insert the new battery into the same holder, making sure it sits flat and the same side faces the same direction as the old one did. Close the fob by pressing the two halves together until you hear or feel a click. Test the buttons to make sure they work. If nothing happens, open it again and check that the battery is seated properly and facing the right way.
If the fob still doesn't work after you've replaced the battery and checked the orientation, the problem may be a damaged circuit board or a stuck button rather than the battery itself. In that case, a locksmith or dealership can diagnose the real issue.
When to take your key to a professional
Take your key to a locksmith or dealership if the fob won't open without risk of breaking it, if you're not comfortable opening it yourself, or if replacing the battery doesn't fix the problem. Some luxury car fobs are glued shut rather than snapped together, and forcing them open can cause permanent damage. A professional can open these safely and replace the battery without harm.
You should also see a professional if your key fob has water damage, visible cracks, or a corroded battery holder inside. Water damage and corrosion can't be fixed by swapping the battery alone—the circuit board itself needs cleaning or replacement. A locksmith or dealership can assess whether the fob can be saved or needs to be replaced entirely.
If your car is still under warranty, check your warranty paperwork before paying for a replacement. Some manufacturers cover key fob battery replacement or replacement fobs at no cost during the warranty period. A quick call to your dealership can tell you whether you're covered.
Cost comparison: DIY versus professional replacement
| Option | Cost | Time to completion | Best for |
|---|---|---|---|
| Replace it yourself | $3–$8 for the battery | 5 minutes | straightforward fobs that open easily; people comfortable with small electronics |
| Locksmith | $20–$75 | 15–30 minutes (often same-day) | Fobs that are hard to open; people who want professional confirmation the fob works |
| Big-box retailer (Best Buy, Walmart) | $10–$30 | 15–30 minutes (often same-day) | Budget-conscious owners; locations near home or work |
| Dealership | $50–$150 | 30 minutes to 1 hour (often same-day) | Luxury or newer cars; fobs with special features; warranty coverage |
The cheapest route is always to do it yourself if your fob opens easily and you have the right battery type. The most reliable route is a locksmith, who can confirm the fob works properly and diagnose other problems if the battery replacement doesn't fix it. Dealerships are the most expensive but are useful if your car is under warranty or if your fob has features a locksmith might not be familiar with.
Finding a locksmith or retailer near you
Search "locksmith near me" or "car key battery replacement near me" in Google Maps or your phone's maps app. Read the reviews and call ahead to confirm they do key fob battery replacement and what they charge. Many locksmiths can fit you in same-day, especially if you call in the morning.
Best Buy and Walmart both offer key fob battery replacement at their customer service desks. Call ahead to check whether your local store offers the service and whether they have your battery type in stock. Some smaller Walmart locations don't offer this service, so confirming first saves a wasted trip.
Your car's dealership can be found by searching "[your car make] dealership near me." Call the service department directly and ask about key fob battery replacement. Some dealerships require an appointment; others take walk-ins. Prices vary by dealership and location, so it's worth calling a few if you have multiple options nearby.
Frequently Asked Questions
Can I use any coin-cell battery, or does it have to be the exact type?
It has to be the exact type—CR2032, CR2025, or whatever your fob requires. Using the wrong size won't fit properly or won't provide the right voltage, and the fob won't work. The battery type is printed on the old battery or in your owner's manual, so check before you buy.
What do I do if I can't get the key fob open?
Stop trying. Forcing it risks cracking the plastic or damaging the circuit board inside. Take it to a locksmith or dealership instead. They have tools designed to open fobs safely without damage, and the cost ($20–$75) is worth avoiding a broken fob.
Will replacing the battery fix a fob that got wet?
Not usually. Water damage corrodes the circuit board and battery contacts, so a new battery alone won't solve the problem. A locksmith or dealership can clean the fob and assess whether it can be saved, but water damage often means the fob needs to be replaced entirely.
How long does a key fob battery last?
Most key fob batteries last three to four years with normal use, though this varies depending on how often you use the fob and the quality of the battery. Batteries in fobs you use dozens of times a day will wear out faster than those in fobs you use only a few times daily.
Can I replace the battery in a smart key or push-button start fob myself?
Many smart keys and push-button fobs use the same coin-cell batteries and can be opened and replaced the same way as a standard fob. However, some luxury car fobs are more complex or glued shut. Check your owner's manual or search your specific car model online before attempting it. When in doubt, take it to a locksmith or dealership.