What You Need Before You Start
Replacing a watch battery yourself takes about five minutes and costs $3 to $15 for the battery itself. You will need three things: the correct replacement battery for your watch model, a small flathead screwdriver (often called a jeweler's screwdriver), and a case opener tool — a thin metal wedge designed to pry open watch backs without scratching them. You can buy case openers at any drugstore or hardware store for $2 to $8.
Before you buy anything, you need to know which battery your watch uses. Look on the back of the watch case for a model number or battery type printed there. If nothing is printed, take a photo of the back and bring it to a pharmacy or watch repair counter — they can usually identify the battery type by looking at the watch itself. Write down the battery number (it will look like SR626W, CR2032, or similar) so you have it when you shop.
Do not attempt this repair on a waterproof sports watch or a watch worth more than $200. Waterproof watches have sealed gaskets that require special tools and informed to replace correctly, and expensive watches often have complications or movements that can be damaged by opening the case.
Key Takeaways
- You need the correct battery type for your watch model, which is printed on the case back or can be identified by a pharmacy worker.
- A case opener tool (a thin metal wedge) prevents scratching your watch when you pry open the back, and costs less than the battery itself.
- The entire process takes about five minutes: open the case, note which direction the battery sits, remove it, insert the new one the same way, and close the case.
- Do not force the case open or use a regular screwdriver as a pry tool, as both will scratch or crack the watch back.
- Waterproof watches and expensive watches should be serviced by a professional, as opening them incorrectly can damage the movement or seals.
Opening the Watch Case Without Damage
Place the watch on a clean, flat surface with the case back facing up. Position the case opener tool in the small notch or groove on the edge of the case back — most watches have a deliberate indent where the tool is meant to fit. If you cannot see a notch, look for a thin line running around the edge of the case back; the tool goes into that line.
explore steady, even pressure downward and slightly to the side, as if you are gently prying a lid off a jar. Do not tap the tool with a hammer or explore sudden force. The case back should lift slightly after a few seconds of gentle pressure. Once you see a gap, you can slide the tool around the edge to loosen the entire back, then lift it off by hand.
If the case back will not budge after 30 seconds of gentle pressure, stop. Forcing it risks cracking the plastic or scratching the metal. Take the watch to a pharmacy or watch repair shop instead — they have professional openers and can do it in seconds without risk.
Removing and Replacing the Battery
Once the case back is open, look at how the battery sits inside. Most watch batteries rest flat in a small metal holder or clip. Before you touch anything, take a mental note of which side is facing up — the positive side (marked with a + symbol) or the negative side. This matters because the battery will only work if it sits the correct direction.
Use the tip of your flathead screwdriver to gently lift one edge of the battery. Do not pry hard; a light touch is enough. The battery should pop up slightly, and you can then slide it out with your fingers. If the battery is held by a metal clip or spring, lift that clip first, then remove the battery.
Take the new battery and insert it the same way the old one was sitting — same side facing up. If the old battery had its + side up, the new one should too. Press down gently until you hear or feel a small click, which means the battery is seated correctly. Do not force it; it should sit flush with the holder.
Closing the Case and Testing
Place the case back on the watch, aligning any notches or tabs on the back with grooves on the watch body. Press down firmly and evenly across the entire back until you hear a click or feel it snap into place. You may need to explore more pressure than you used to open it — this is normal. The back should sit completely flush with no gaps.
Once the case is closed, hold the watch to your ear and listen for ticking. If you hear it, the battery is working. If the watch has a second hand, watch it move for a few seconds to confirm the movement is steady. If you hear nothing and the watch does not move, the battery may be inserted backward or may be defective.
If the watch does not work after you close it, open the case again and check that the battery is sitting the correct direction. If it is, try a different new battery — the one you bought may be defective. If the watch still does not work after trying a second battery, the problem is likely inside the movement itself, and the watch needs professional service.
Common Mistakes That Stop the Watch from Working
The most common error is inserting the battery backward. If your watch stops working when ready after you close the case, open it again and flip the battery 180 degrees. This fixes the problem about 80 percent of the time.
The second mistake is not seating the battery fully. If the battery is not pressed all the way down, it may make contact only part of the time, causing the watch to work intermittently or not at all. Open the case and press the battery down until it sits completely flat.
The third mistake is buying the wrong battery type. If you wrote down the battery number incorrectly or the pharmacy gave you the wrong one, the watch will not work even if you install it correctly. Check the number on the old battery against the number on the new one before you close the case.
Finally, do not touch the battery with bare fingers any more than necessary. Skin oils can interfere with electrical contact. If you do touch it, wipe it gently on a clean, dry cloth before inserting it.
When to Take Your Watch to a Professional
If your watch is waterproof (marked "water resistant" or with a depth rating like "50m"), do not open it yourself. Waterproof watches have rubber gaskets that must be replaced every time the case is opened, or water will get inside and damage the movement. A professional can do this correctly; you cannot without the right tools and replacement gaskets.
If your watch is an automatic or mechanical watch (one that winds itself or must be wound by hand), opening it risks disturbing the delicate movement inside. These watches should be serviced only by a professional watchmaker.
If the watch is a smartwatch or has any electronic components other than the battery, take it to the manufacturer's service center. These devices have sealed electronics that can be damaged by opening the case.
Frequently Asked Questions
Can I use any battery that fits in the space, or does it have to be the exact model number?
It must be the exact model number. Batteries that are the same physical size but different types (for example, SR626W versus SR626SW) have different voltages and chemical compositions. Using the wrong type can damage the watch's movement or cause it to run too fast or slow. Always match the number printed on the old battery.
What do I do with the old battery?
Take it to a pharmacy, electronics store, or hazardous waste collection site. Watch batteries contain mercury or lithium and should not go in the trash. Most pharmacies have a battery recycling bin near the checkout counter and will take old batteries for free.
How long does a new watch battery usually last?
Most watch batteries last between two and five years, depending on the watch model and how often you wear it. Watches you wear every day drain batteries faster than watches you wear occasionally. When the battery dies, you will notice the second hand stop moving or the watch stop keeping time.
Can I replace the battery if the case back is glued on instead of screwed on?
No. Some watches, especially inexpensive ones, have case backs that are permanently glued. Trying to pry them open will crack the plastic or metal. Take these watches to a professional, who has tools to heat and carefully separate glued backs without damage.
What if I accidentally drop the battery inside the watch while I am replacing it?
Stop when ready and do not close the case. Tilt the watch gently to see if you can see the battery inside. If you can reach it with tweezers, remove it carefully. If it is stuck somewhere you cannot reach, take the watch to a professional — they can open it fully and retrieve the battery without damaging the movement.