Most car key fob batteries last three to four years and cost $3 to $10 to replace

You can replace a dead key fob battery yourself in about five minutes using a coin and a fresh battery from any drugstore or supermarket. The battery type varies by fob model — most common cars use CR2032, CR2025, or CR2016 — but you can find the right one by checking your owner's manual or taking the old battery to a store employee. The whole job requires no tools beyond a coin or flathead screwdriver to pry the fob open.

If you do not want to do it yourself, any car dealership, tire shop, or battery retailer will replace it for you, usually while you wait. Some charge a small fee; others do it free. The dealership route takes longer and costs more, but guarantees the fob works when you leave.

Key Takeaways

  • Most key fob batteries cost between $3 and $10 and are sold at drugstores, supermarkets, and online retailers.
  • The correct battery type is printed in your owner's manual or on the back of your current fob, and common types are CR2032, CR2025, and CR2016.
  • You can open most fobs with a coin or flathead screwdriver by prying at the seam between the two halves.
  • If the fob still does not work after you replace the battery, the problem is likely the circuit board or buttons, not the battery itself.

Finding out what battery your fob needs

The easiest way is to open the fob and look at the old battery. The battery type is stamped on the flat side — you will see something like CR2032 or CR2025. Write this down or take a photo with your phone.

If you cannot open the fob or the old battery is too corroded to read, check your owner's manual. Search the index for "key fob" or "remote battery" and the manual will list the type. If you do not have the manual, search online for your car's year, make, and model plus "key fob battery" — most manufacturer websites list this information.

Once you know the type, you can buy the battery at a drugstore, supermarket, big-box retailer, or online. Most stores stock CR2032 because it is the most common type. The battery usually costs $3 to $8 depending on the brand and where you buy it.

Opening the fob and removing the old battery

Look for a seam running around the edge of the fob where the two plastic halves meet. This seam is usually on the side or the back. Slide a coin (a penny or dime works well) or a flathead screwdriver into the seam and gently twist to pry the two halves apart. Do not force it — if it does not budge, try a different spot along the seam.

Once the fob is open, you will see the battery sitting in a small metal holder. Note which side is facing up — the flat side with the + symbol should face up in most fobs. Gently pry the battery out with your fingernail or the edge of the coin. If it is stuck, a small piece of tape under the edge can help you lift it.

If the battery is corroded or leaking, wipe the inside of the battery holder with a dry cloth or a cotton swab before you put the new battery in. Corrosion can prevent the new battery from making good contact.

Installing the new battery and closing the fob

Place the new battery into the holder with the + side facing up, the same direction the old one was facing. Press it down gently until it sits flat in the holder. You should hear or feel a small click as it settles into place.

Align the two halves of the fob and press them together firmly until you hear a click. Start at one end and work your way around the seam to make sure both halves are seated evenly. The fob should feel solid when you squeeze it — if there is a gap or it feels loose, open it again and check that the battery is sitting flat.

Test the fob by pressing each button while standing near your car. You should see the car's lights flash or hear the locks click. If nothing happens, open the fob again and make sure the battery is facing the right direction and sitting all the way down in the holder.

What to do if the fob still does not work

If the fob does not work after you replace the battery, the problem is usually not the battery. The most common cause is a worn-out button contact or a damaged circuit board inside the fob. Both of these require replacing the fob itself, not just the battery.

Before you assume the fob is broken, try cleaning the battery contacts. Open the fob again, remove the battery, and wipe the metal contacts inside the holder with a clean, dry cloth or a cotton swab. Sometimes a thin layer of corrosion or dust prevents the battery from making good contact. Reinstall the battery and test again.

If the fob still does not work, contact your car's dealership for a replacement fob. Dealerships can order a new fob and program it to your car, though this usually costs $150 to $400 depending on the car model. Some aftermarket fobs are cheaper and work with most cars, but the dealership is the safest option if you want to be certain it will work.

Getting the battery replaced at a store or dealership

If you do not want to replace the battery yourself, take the fob to any of these places: your car's dealership, a tire shop (Discount Tire, Firestone, Goodyear), a battery retailer (Batteries Plus), or a big-box store with a service counter (Best Buy, Walmart). Most of these places will replace the battery while you wait, usually in 10 to 15 minutes.

Call ahead to confirm they offer this service and ask whether there is a charge. Many tire shops and dealerships do it free or for a small fee ($5 to $15). Some battery retailers include it free with the battery purchase. The dealership is usually the most expensive option but guarantees the fob will work when you leave.

Extending the life of your new battery

Key fob batteries last longest when the fob is not exposed to extreme heat, cold, or moisture. Keep the fob away from direct sunlight, do not leave it in a hot car, and avoid dropping it or sitting on it. If the fob gets wet, open it and let the inside dry completely before closing it again.

Avoid using the fob unnecessarily — every button press drains the battery a tiny amount. If you use the fob multiple times a day, the battery may last only two to three years instead of four. If you use it rarely, it may last five years or longer.

Frequently Asked Questions

Can I use a different battery type if I cannot find the exact one?

No. Battery types like CR2032, CR2025, and CR2016 have different thicknesses and voltages, and using the wrong one can damage the fob's circuit board or cause it to malfunction. Always use the exact type listed in your manual or on the old battery.

What if the fob battery compartment is sealed and I cannot open it?

Some luxury cars have fobs that are not designed to open. If you cannot find a seam after looking carefully, take the fob to your dealership. They have tools to open sealed fobs and can replace the battery for you, usually for a small fee.

How do I know if my fob battery is dead or if the fob is broken?

A dead battery is the most common reason a fob stops working. If the fob has not been used in months or the buttons feel sluggish, the battery is likely dead. If you replace the battery and the fob still does not work, the circuit board or buttons are probably damaged and the fob needs to be replaced.

Is it safe to throw away the old battery?

Lithium batteries like CR2032 can be recycled. Many drugstores and supermarkets have battery recycling bins near the checkout or customer service desk. You can also take old batteries to a battery retailer or your local recycling center. Do not throw them in the trash.

Can I replace the battery in a smart key or push-button fob?

Yes, the process is the same. Smart keys and push-button fobs use the same battery types as traditional fobs. Open the fob the same way — look for a seam and pry it open with a coin — and replace the battery following the same steps.