Most key fob batteries are sold at drugstores, supermarkets, and auto parts stores for $3 to $8

You do not need to go to a dealership or a specialist. The battery inside your key fob is a standard coin cell battery—the same type used in watches, calculators, and hearing aids. You can buy one at any pharmacy, grocery store, or auto parts chain. The catch is knowing which size your fob needs before you walk in, because they come in several versions and one wrong size will not fit.

The most common sizes are CR2032, CR2025, and CR2016. Your owner's manual will tell you which one, or you can open the fob yourself and read the number stamped on the old battery. Once you know the size, you have several places to choose from, and the price is nearly identical everywhere.

Key Takeaways

  • Check your owner's manual or open the fob to find the battery size (usually CR2032, CR2025, or CR2016) before you shop.
  • Drugstores like CVS and Walgreens, supermarkets, and auto parts chains like AutoZone all stock coin cell batteries for $3 to $8.
  • Dealerships will replace the battery for you but charge $50 to $100 for labor, which is unnecessary for a five-minute job.
  • Replacing the battery yourself takes less than five minutes and requires no tools other than a coin or flathead screwdriver to pry the fob open.

Drugstores and supermarkets carry the most common sizes

CVS, Walgreens, Rite Aid, and most supermarket chains stock coin cell batteries in their pharmacy or health and beauty section. They typically have CR2032 and CR2025 in stock because those are the most common sizes for car key fobs. A single battery costs $4 to $6, and you can buy it without a membership or a minimum purchase.

The advantage here is convenience—you can grab one while you are already shopping for something else. The disadvantage is that smaller locations may not stock less common sizes like CR2016 or CR2430. Call ahead if your fob needs an unusual size, or ask the pharmacy staff to check their system.

Auto parts stores stock a wider range and often have bulk packs

AutoZone, O'Reilly Auto Parts, Advance Auto Parts, and NAPA all carry coin cell batteries and usually have more sizes in stock than a drugstore. They also sell multi-packs—a 4-pack of CR2032 batteries costs around $8 to $10, which is cheaper per battery if you have multiple fobs or want spares on hand.

These stores are staffed by people who work with car parts daily, so they can help you identify the right size if you are unsure. Many will also open your fob for you and install the battery while you wait, usually at no charge if you bought the battery from them. This is a real convenience if you are uncomfortable opening the fob yourself.

Online retailers offer the lowest per-battery cost but require planning ahead

Amazon, eBay, and battery-specific sites like Batteries Plus sell coin cell batteries in bulk at lower prices than brick-and-mortar stores. A 10-pack of CR2032 batteries can cost $6 to $8, bringing the per-battery cost down to under $1. The trade-off is shipping time—you will wait two to five days for delivery, so this only works if your fob is not dead yet.

This route makes sense if you have multiple vehicles, multiple fobs, or if you want to keep spares in a drawer. It does not make sense if your fob stopped working yesterday and you need it today.

Dealerships will replace it but charge for labor you do not need

Your car dealership can replace the battery, and they will do it correctly. The cost is usually $50 to $100 in labor, plus the cost of the battery itself. Some dealerships will do it while you wait; others may keep your fob for a day.

This is the wrong choice unless you are uncomfortable opening the fob yourself or you suspect the fob has a deeper problem. For a straightforward battery replacement, you are paying for convenience you do not need. A dealership makes sense only if the fob stops working after you replace the battery, because then the problem is electrical rather than just a dead cell.

How to identify your battery size before you shop

The easiest way is to check your owner's manual. Search for "battery" in the index, and it will tell you the exact size. If you do not have the manual, you can find it online by searching "[your car year, make, model] owner's manual PDF."

If you want to know right now, you can open the fob yourself. Most key fobs have a seam you can pry open with a coin or a flathead screwdriver—push gently along the seam until the two halves separate. The battery will be sitting in a small slot, and the size is printed on its surface. Write down the number (it will be something like CR2032) and take a photo with your phone so you have it when you shop.

What to do if you cannot find your battery size in stock

If a store does not have your size, ask them to order it. Most drugstores and auto parts chains can order a battery and have it in one to three days. You can also call other nearby locations to see if they have it in stock before you drive around.

If you are in a hurry and your size is uncommon, an online order with two-day shipping may be faster than waiting for a store order. Amazon Prime members can often get batteries delivered the next day. In the meantime, keep your fob in your pocket and use the physical key to unlock your car—the fob will still work for locking once you replace the battery.

Frequently Asked Questions

Can I use a different size battery if my size is not in stock?

No. The battery has to fit physically in the slot, and the voltage has to match what the fob expects. Using the wrong size can damage the fob's circuit board or cause it to malfunction. Wait for the correct size or order it online.

Do I need to reprogram my key fob after I replace the battery?

No. Replacing the battery does not erase any programming. The fob will work exactly as it did before, as soon as you snap it back together. If it does not work after you replace the battery, the problem is not the battery.

How long does a key fob battery usually last?

Most coin cell batteries last three to four years in a key fob, depending on how often you use it. If you press the buttons dozens of times a day, the battery may wear out faster. There is no way to predict exactly when it will die, so keep a spare on hand.

Is it safe to replace the battery myself?

Yes. You are just swapping out a battery—there is no risk of electrical shock or damage to the car. The only thing to be careful about is not dropping the small battery or the tiny spring inside the fob. Work over a table or a towel so you can find it if it rolls away.

What if my key fob still does not work after I replace the battery?

The problem is likely not the battery. The fob may have water damage, a broken button, or a dead circuit board. Try replacing the battery one more time to make sure it is seated correctly, then contact your dealership. They can test the fob and tell you whether it can be repaired or needs to be replaced.