You can replace a Timex watch battery yourself with a coin, a small screwdriver, and about five minutes

Most Timex watches have a screw-back case that opens from the rear. You do not need special tools or a jeweler—just a flathead screwdriver that fits the slot, a coin to grip the case back, and the correct replacement battery. The whole job takes longer to find your tools than to do the work. The hardest part is not losing the tiny screws.

Before you start, you need to know your watch model number and the battery type it uses. Check the back of the watch case or the original paperwork. Common Timex batteries are SR626SW, SR927SW, and 395/399. Once you have the right battery, the replacement process is the same for nearly every Timex model with a screw-back case.

Key Takeaways

  • Timex watches with screw-back cases open from the rear using a flathead screwdriver and a coin to grip the case back.
  • You must know your battery type before you buy a replacement—check the watch case back or original paperwork for the model number.
  • Replacement batteries cost between $3 and $8 and are sold at drugstores, hardware stores, and online retailers.
  • The battery sits in a small metal holder called a battery contact; make sure it stays in place when you close the case.
  • If the watch does not start after you replace the battery, the battery contact may not be touching the battery, or the new battery may be dead.

Find the right replacement battery for your Timex model

The battery type is printed on the back of your watch case or inside the paperwork that came with it. Look for a code like SR626SW, SR927SW, 395, or 399. If you cannot find the model number on the watch itself, search online for your specific Timex model—the manual or product page will list the battery type.

Once you know the battery code, buy a replacement at a drugstore, supermarket, hardware store, or online. Timex watches use standard watch batteries that any retailer sells. Do not buy the cheapest option; a name-brand battery from Energizer, Maxell, or Panasonic costs a few dollars more and lasts longer. Keep the receipt and packaging in case the battery is defective.

Gather your tools and prepare your workspace

You need a flathead screwdriver that fits snugly into the slot on the case back, a coin (a dime or penny works), and a clean, flat surface with good light. A small bowl or cup is useful for holding the screws so you do not lose them. Lay a soft cloth on your work surface to prevent the watch from sliding and scratching.

Wash your hands before you start. Oils and dirt on your fingers can interfere with the battery contact and prevent the watch from working. If your hands are very oily, wipe them on a lint-free cloth before touching the battery or the inside of the watch.

Open the case back by unscrewing it

Place the watch face-down on your cloth. Locate the slot on the case back—it usually runs across the center or sits near the edge. Insert the flathead screwdriver into the slot and turn it counterclockwise, the same direction you would unscrew a regular screw. Turn slowly and steadily; do not force it. If the screwdriver does not fit snugly, try a different size—a loose fit will slip and damage the slot.

Once the case back is loose enough to grip, use the coin to turn it the rest of the way. Hold the watch body steady with one hand and turn the coin counterclockwise with the other. The case back will come free. Set it down in a safe place where you will not lose it.

Remove the old battery and install the new one

Look inside the watch. You will see the battery sitting in a small metal holder, usually in the center. The battery is round and flat, about the size of a small button. Gently pry it out with the edge of your screwdriver or a plastic tool—do not use a sharp metal object that could scratch the inside of the watch. Set the old battery aside.

Before you insert the new battery, check that the metal contact—a small spring or tab inside the holder—is still in place and not bent. If it is bent, straighten it gently with your screwdriver. Now place the new battery into the holder with the positive side (marked with a + or the shiny side) facing up. The battery should sit flat and not rock. If it does not fit snugly, remove it and check that you have the correct battery type.

Close the case back and test the watch

Hold the watch body steady and align the case back so the slot lines up with the screwdriver. Insert the screwdriver and turn clockwise to tighten. Do not overtighten—turn until you feel resistance, then stop. If you force it, you can strip the threads and damage the case. Once the screwdriver is snug, use the coin to turn it a quarter turn more to may support a tight seal.

Press the crown (the knob on the side of the watch) or any button to see if the watch starts. If it does, the battery is installed correctly. If it does not, remove the case back again and check that the battery is sitting flat in the holder and that the metal contact is touching the battery. A battery that rocks or a contact that is bent will prevent the watch from working.

What to do if the watch still does not work

If the watch does not start after you close the case, the most common cause is that the battery contact is not touching the battery. Remove the case back and press down gently on the metal contact to make sure it is making contact with the battery. If the contact is bent away from the battery, use your screwdriver to bend it back into place.

The second most common cause is a defective new battery. If the contact is touching the battery and the watch still does not work, try a different battery from the same package or a different brand. If a second battery also does not work, the watch may have a problem inside that requires professional repair. Take it to a jeweler or Timex service center.

Frequently Asked Questions

Can I replace the battery in a Timex watch with a screw-on case back?

Yes. Screw-on case backs are the most common type on Timex watches. Use a flathead screwdriver to turn the slot counterclockwise until it is loose, then use a coin to finish unscrewing it by hand. The process is the same as described above.

What if my Timex watch has a snap-on case back instead of a screw-on?

Snap-on case backs require a case opener tool that you can buy at a watch repair shop or online for $10 to $20. The tool has a notch that fits into a small groove on the case back. If you do not want to buy the tool, a jeweler or watch repair shop can open it for you for a few dollars.

How long does a Timex watch battery usually last?

Most Timex watch batteries last between two and five years, depending on the watch model and how often you use it. Watches with a second hand or a backlight drain the battery faster. A battery that dies in less than a year is usually defective.

Do I need to reset the time after I replace the battery?

No. The time will continue from where it stopped when the old battery died. Once you install the new battery and the watch starts, the time will be wrong, but you can adjust it using the crown the same way you normally set the time.

What should I do with the old battery?

Take the old battery to a drugstore, hardware store, or electronics retailer that has a battery recycling program. Many stores accept used batteries for free. Do not throw it in the trash—batteries contain materials that should be recycled.