Open the key fob case first
Most key fobs split into two halves along a seam that runs around the edge. Look for a small slot or notch on the side — this is where you insert a flat tool to pry the case apart. A coin, flathead screwdriver, or plastic pry tool works well. Insert it gently into the slot and twist slightly; the case will pop open without much force.
If you cannot find a visible seam, check whether your fob has a button on the back or a small screw. Some fobs have a sliding battery cover on the back instead of a split case — slide it in the direction of the arrow printed on the plastic. A few older or premium fobs use a single screw; unscrew it and the case will come apart.
Do not force the case. If it is not budging, you are likely prying in the wrong spot. Rotate the fob and look for the seam again — it is usually a thin line running horizontally or vertically around the middle.
Key Takeaways
- The battery sits in a metal holder inside the case and is held down by a small clip or spring that you lift gently to release it.
- Write down the battery type number before you remove the old one so you buy the correct replacement — common types are CR2032, CR2025, and CR2016.
- The battery slides or pops out once the clip is lifted; do not pry it or force it sideways.
- Reassemble the case by pressing the two halves together until you hear or feel a click, and test the fob before you put it away.
Locate and lift the battery clip
Once the case is open, you will see the battery sitting in a metal or plastic holder. A small metal clip or spring arm holds it down. This clip is usually on one edge of the battery — often the top or side. Gently lift or slide this clip away from the battery. It requires only light pressure; if you are straining, you are likely lifting the wrong part.
Some fobs have a plastic tab instead of a metal clip. Pull this tab straight up or to the side, depending on how it is oriented. The battery will then sit loose in the holder and can be removed by hand.
Remove the old battery and note its type
Once the clip is released, the battery should lift out easily. Before you throw it away, look at the top surface — you will see a number stamped or printed on it, such as CR2032, CR2025, or CR2016. Write this number down or take a photo. This is the battery type you need to buy as a replacement.
If the number is hard to read, the battery holder itself often has the type printed inside. Look at the bottom of the metal cup where the battery sat. If you still cannot find it, the most common type for car key fobs is CR2032, but do not guess — ask the cashier at the store to match the old battery, or search online for your vehicle's make and model plus "key fob battery type."
Insert the new battery correctly
Batteries have a positive side (marked with a + or a flat top) and a negative side (marked with a − or a recessed bottom). The positive side almost always faces up, toward the top of the fob. Slide or place the new battery into the holder with the + side up, then press the clip back down over it until you hear or feel it click into place.
Do not force the clip. It should settle over the battery smoothly. If it is resisting, the battery may be slightly misaligned — lift the clip, adjust the battery position, and try again.
Close the case and test the fob
Press the two halves of the case together firmly until they click or snap. You should feel them seat fully — there should be no gap or wiggle along the seam. If the case does not close flush, open it again and check that the battery is sitting flat and the clip is not bent.
Once closed, test the fob by pressing each button while standing near your vehicle. The lights should flash and the doors should lock and unlock. If nothing happens, open the case again and check that the battery is inserted with the + side up and the clip is holding it firmly. If the fob still does not work after you have confirmed the battery is correct and properly seated, the fob itself may need repair — contact your vehicle's dealer or a locksmith.
Where to buy replacement batteries
Key fob batteries are sold at pharmacies, grocery stores, hardware stores, and online retailers. They cost between $3 and $8 per battery. You can buy them individually or in packs of two or four. Bring the old battery with you to the store so the cashier can confirm you are buying the right type, or order online using the battery number you wrote down.
Some car dealerships sell key fob batteries, but they usually charge more than retail stores. If you are already at the dealership for another service, it may be convenient, but there is no reason to pay a premium for a battery you can replace yourself in two minutes.
Frequently Asked Questions
What if the case will not open?
Look more carefully for the seam — it is usually a thin line, not a thick groove. Try inserting your pry tool at a different spot along the edge. If your fob has a screw, make sure you have a screwdriver that fits snugly; a loose fit will strip the screw head. If you are still stuck, a locksmith or car dealer can open it for you.
Can I use a different battery type if I cannot find the exact one?
No. CR2032, CR2025, and CR2016 are different sizes and voltages. Using the wrong type can damage the fob's circuit board or cause it to malfunction. Always match the number on the old battery or the holder. If you cannot find your type in stock, order it online rather than substituting.
How long does a key fob battery last?
Most key fob batteries last three to four years with normal use. If you use your fob frequently, it may last two to three years. If you rarely use it, it may last longer. There is no way to predict exactly when it will die, so replace it as soon as the fob stops responding to button presses.
Is it safe to handle the battery with bare hands?
Yes. Coin cell batteries like CR2032 are safe to touch. Wash your hands afterward if you prefer, but there is no hazard from brief contact. Do not swallow the battery or let children play with it — if swallowed, seek medical attention when ready.
What do I do with the old battery?
Most retailers that sell batteries also have a battery recycling bin near the checkout. Drop your old battery there. Do not throw it in the trash — batteries contain materials that should be recycled. If the store does not have a bin, ask the cashier where the nearest recycling center is.