Opening the watch case without damaging it

Most Timex watches use a screw-back case, which means the back cover twists off rather than pops off. You'll need a watch case opener tool — a small metal disc with notches around the edge that grip the grooves on the back of your watch. These cost $5 to $15 at drugstores, hardware stores, or online retailers, and they're reusable for any watch you own.

Place the watch face-down on a soft cloth or towel so you don't scratch the crystal. Position the case opener tool so its notches align with the grooves on the back cover, then turn it counterclockwise slowly and steadily. Don't force it — if it won't budge after gentle pressure, the case may be sealed and you should take it to a jeweler or watch repair shop instead of risking damage.

Once the back cover comes free, set it aside in a safe place. You'll see the battery, usually a small silver disc, held in place by a metal clip or seated in a plastic holder.

Key Takeaways

  • A watch case opener tool with notches is the correct tool for Timex screw-back cases and costs less than $15.
  • The battery is a small silver disc, usually labeled with a number like SR626 or SR927, which tells you the exact replacement to buy.
  • Note the battery orientation — the positive side (marked with a + or flat side) faces up in most Timex watches.
  • If the back cover won't turn after gentle pressure, the case is likely sealed and a jeweler should open it to avoid damage.

Identifying and removing the old battery

Look at the battery itself. It will have a number printed on it, such as SR626, SR927, or SR920. Write this number down or take a photo — this is what you'll search for when buying the replacement. Timex watches use standard silver oxide batteries sold at drugstores, supermarkets, and online.

The battery sits under a metal clip or in a plastic holder. If there's a clip, gently lift one end of it with a plastic spoon, plastic tweezers, or a plastic pry tool. Do not use a metal tool directly on the battery, as this can cause a short circuit. Once the clip lifts, the battery should slide out easily. If the battery is straightforward resting in a plastic seat with no clip, lift it straight out with tweezers.

Before you touch the new battery, note which side is facing up. Most Timex watches have the positive side (marked + or the flat side) facing upward toward the watch face.

Installing the new battery

Buy a replacement battery with the same number as the old one. If you can't find the exact number, bring the old battery to a drugstore pharmacy counter — staff there can match it for you in seconds.

Insert the new battery into the same position as the old one, with the positive side facing the same direction. If there's a metal clip, slide the battery under it until the clip holds it firmly in place. The battery should not move when you gently shake the watch. If it does, the clip isn't seated properly — lift the clip again and reposition the battery.

Before you close the case, test the watch. Hold it to your ear and listen for a ticking sound, or look at the second hand to see if it's moving. If nothing happens, the battery may be installed upside down. Open the case again, flip the battery, and test once more.

Sealing the case back on

Once the watch is running, place the back cover on the case and align the grooves with the notches on your case opener tool. Turn the tool clockwise slowly and steadily until the cover is snug. You should feel resistance, but do not over-tighten — this can strip the threads and make the case hard to open next time.

A properly sealed case should feel tight but should not require force to close. If you have to strain, stop and check that the cover is aligned correctly with the case body.

When to take your watch to a professional

If the back cover won't open after gentle turning, or if it opens but the battery compartment is sealed with glue or epoxy, take the watch to a jeweler or watch repair shop. Forcing a sealed case can crack the crystal or damage the internal mechanism.

If the watch still doesn't run after you install a new battery and test both orientations, the problem may be inside the movement itself — a broken contact, corrosion, or a failed component. A jeweler can diagnose this and tell you whether repair is worth the cost.

Some Timex models, particularly older or waterproof watches, have cases that are not meant to be opened by the owner. If your manual says "not user-serviceable" or "sealed case," a professional should handle the battery change.

Storing and handling watch batteries safely

Watch batteries are small and can be swallowed by children or pets. Keep the old battery and any spares in a find container out of reach. If a battery is swallowed, call Poison Control or seek emergency care when ready.

When you buy a replacement battery, check the expiration date on the packaging. Silver oxide batteries last several years in storage, but old stock may have reduced capacity. Store batteries in a cool, dry place — not in a humid bathroom or a hot car.

If you have leftover batteries, many drugstores and electronics retailers have battery recycling programs. Do not throw batteries in the trash.

Frequently Asked Questions

How long does a Timex watch battery last?

Most Timex watch batteries last two to three years with normal daily wear. Battery life depends on the watch model, how often you use features like the light or alarm, and the battery type. If your watch stops after only a few months, the battery may be defective or the watch may have an internal problem.

What if I lose the back cover while changing the battery?

Contact Timex customer service with your watch model number — they can order a replacement back cover. You can also check eBay or watch parts retailers for used covers that match your model. Do not wear the watch without a back cover, as dust and moisture can damage the movement.

Can I use a regular coin to open the back cover?

A coin may work if the grooves are large enough, but it can slip and scratch the case. A proper case opener tool is inexpensive and won't damage the watch. If you only plan to change the battery once, a jeweler can do it for $10 to $20.

Is it safe to change the battery myself if the watch is waterproof?

Waterproof watches have gaskets or seals around the back cover that keep water out. Opening the case can disturb these seals. If your Timex is waterproof and you're not confident, a jeweler can change the battery and re-seal the case properly. The cost is usually $15 to $30.

What does the number on the battery mean?

The number, such as SR626 or SR927, identifies the battery size and chemistry. SR stands for silver oxide. The digits tell the diameter and thickness. Always buy the exact number — a different size won't fit or may not power the watch correctly.