You can change most watch batteries at home with a small tool kit and 10 minutes

Changing a watch battery is a task you can do yourself if the watch case opens from the back. You need a case opener (a flat tool that pries the back off), a small screwdriver, tweezers, and a fresh battery in the correct size for your model. The whole job takes about 10 minutes once you have the right tools and know which battery your watch uses. If your watch is sealed or has a screw-down case back, a jeweler or watch repair shop is the safer choice — forcing it open can damage the water resistance or crack the crystal.

Key Takeaways

  • Most watches use a three-digit battery code (like SR626 or LR44) printed on the old battery or in the watch manual, and you must match it exactly.
  • A case opener tool costs $5 to $15 and is the only tool most people need to buy; tweezers and a small screwdriver are usually at home already.
  • Watches with screw-down case backs or sealed designs should go to a jeweler, because opening them wrong can break the water seal or scratch the crystal.
  • The battery sits in a metal holder called a contact, and you must remove it without bending the contact or leaving fingerprints on the new battery.
  • After you close the case back, test the watch to make sure it runs, because a loose battery or misaligned contact will stop it when ready.

Find the right battery size for your watch

The battery code is printed on the old battery itself. Open the case back (see the next section), remove the battery with tweezers, and look at the flat side. You will see a three-digit or four-digit code like SR626, LR44, or 371. Write this code down — it is the only number that matters.

If the old battery is too corroded to read, check the watch manual or the back of the case, where the code is sometimes stamped. If you still cannot find it, take the watch to a jeweler and ask them to tell you the battery code. Do not guess. A battery that is close in size will not work and may damage the watch.

Once you have the code, buy the replacement at a pharmacy, supermarket, or online. Batteries with the same code are interchangeable — a SR626 from any brand will work in any watch that uses SR626. The cost is usually $3 to $8 per battery.

Gather your tools and prepare your workspace

You need four things: a case opener tool, a small flathead screwdriver, tweezers, and the new battery. A case opener is a flat metal pry tool designed to fit into the groove on the back of the watch case. You can buy one online for $5 to $15, or borrow one from a jeweler if you ask politely.

Work on a clean, flat surface with good light — a kitchen table or desk works fine. Lay out a small cloth or paper towel to catch the old battery and any small parts. Watches are small, and parts roll away easily. If your watch has a screw-down case back (you will see a groove all the way around the edge), do not use a case opener — use a case wrench instead, which is a specialized tool that fits the grooves. If you do not have one, a jeweler has the right tool and should charge $10 to $20 to open and close the case.

Open the case back without damaging the watch

Look at the back of the watch. Most watches have a smooth or slightly grooved case back with a small notch or slot on one edge. This notch is where the case opener goes. Insert the flat end of the opener into the notch and gently pry upward. Do not force it — if it does not move after light pressure, you may have the wrong tool or the wrong type of case back. Stop and take the watch to a jeweler instead.

Once the case back starts to lift, work your way around the edge, prying a little at a time. The back will come off in one piece. Set it aside on your cloth so you do not lose it. You will now see the battery, the metal contact that holds it, and possibly a small plastic gasket (a rubber ring that keeps water out). Do not lose the gasket — it goes back in the same position.

Remove the old battery and install the new one

Use tweezers to lift the old battery straight up and out of the metal contact. The contact is a small U-shaped or L-shaped piece of metal that holds the battery in place. Look at how it sits — the new battery must go in the same way, with the positive side (marked with a + or a flat top) facing up toward the contact.

Before you insert the new battery, wipe it gently with a clean, dry cloth. Oils from your fingers can interfere with the electrical connection. Pick it up with tweezers by the edge, not the flat surfaces. Slide it into the contact so it sits flat and level. The contact should hold it snugly without you having to force it. If the contact is bent or loose, do not close the case — take the watch to a jeweler, because a loose battery will fall out or lose contact and stop the watch.

Close the case back and test the watch

If your watch had a gasket, make sure it is still in place around the edge of the case opening. Align the case back with the body of the watch and press down firmly. You should hear or feel a small click as it seats. If it does not click and the back sits flush, it is closed correctly. If there is a gap or the back feels loose, open it again and check that the gasket is in the right position.

Once the case is closed, hold the watch to your ear and listen for a ticking sound. If you hear it, the battery is working. If the watch has a second hand, watch it move — it should sweep smoothly or tick once per second, depending on the watch type. If the watch does not start, open the case back again, remove the battery, and check that the contact is not bent. Reinstall the battery, making sure it sits flat and level. If it still does not work after a second try, the contact may be damaged and the watch needs a jeweler.

When to take your watch to a professional instead

Do not open the case yourself if your watch has a screw-down back, a sealed design, or if you see no obvious notch or slot for a case opener. Watches with these designs are harder to open without the right tool, and forcing them can crack the crystal, bend the case, or break the water seal. A jeweler has the correct tools and will charge $10 to $30 to open, change the battery, and close the case.

If your watch is very old, very expensive, or has sentimental value, a jeweler is also the safer choice. They can also check the gasket and contacts while the case is open, and they can test the water resistance after closing it. If you open the case yourself and then find the watch no longer keeps water out, a jeweler will have to re-seal it, which costs more than the original battery change would have.

Frequently Asked Questions

What if I cannot find the battery code?

Check the watch manual, the back of the case, or the inside of the case back itself — manufacturers sometimes stamp the code there. If none of these work, a jeweler can open the watch and read the old battery for you, then tell you the code. This usually costs $5 to $10.

Can I use a different battery if it is close to the right size?

No. A battery that is slightly different in size or voltage will not work reliably and may damage the watch's circuit. Always match the code exactly. If you cannot find the exact battery, a jeweler can order it or suggest a verified alternative.

How long does a watch battery last?

Most watch batteries last two to five years, depending on the watch type and how often you wear it. Watches you wear every day drain the battery faster than watches you wear occasionally. When the battery dies, the watch straightforward stops — it will not damage the watch to leave it unworn.

What should I do with the old battery?

Most watch batteries contain mercury or other metals and should not go in the trash. Take the old battery to a pharmacy, electronics store, or recycling center that accepts batteries. Many places that sell watch batteries will also take old ones back for free.

Will opening the case back make my watch lose its water resistance?

Not if you close it correctly. The gasket (rubber ring) is what keeps water out, and as long as it is clean and in the right position when you close the case, the water resistance stays the same. If you are unsure about the gasket or the seal, have a jeweler close the case and test the water resistance for you.