How to Change a Watch Battery (And When to Pay Someone Instead)

A quartz watch stops because a cell costing a few pounds has run flat. Changing it takes about ten minutes and a set of tools that cost less than a single jeweller's visit. It also takes some care: the part that goes wrong is rarely the battery, it is the seal that keeps water out afterwards.

First, confirm it is the battery

Before you open anything, check the obvious. A watch that has stopped completely, with no ticking and a second hand frozen in place, is almost always a flat cell. A watch that runs but loses time is a different problem — usually a magnetised movement or a failing module, and a new battery will not fix it.

Also check the crown. A crown pulled out to the setting position stops the seconds hand on many movements. Push it in before you reach for tools.

What you need

• The right cell — the number is printed on the old battery, usually something like 377, 371 or CR2016. Buy the same number.
• A caseback tool — either a case wrench for screw-back cases or a case knife for snap-back cases.
• Fine tweezers — plastic-tipped if you can find them, to lift the cell without shorting it.
• A soft cloth and a clean, well-lit surface — small springs and gaskets disappear instantly on a carpet.

Opening the caseback

There are three common types, and each opens differently.

Snap-back

Look for a small lip or notch between the caseback and the case. Insert a case knife into the notch and lever gently — the back should pop free. Work slowly and do not pry at the crystal side.

Screw-back

The caseback has six or eight notches around the edge. A case wrench with adjustable pins engages two of them; turn anticlockwise. If it is tight, apply steady pressure rather than force — a slipped wrench scratches the back badly.

Screw-down (screwed caseback with a full thread)

Common on dive-style watches. These use a dedicated tool or a large rubber ball for grip. If you have to ask which type you have, it is probably this one, and it is the type most easily damaged.

Swapping the cell

Note the orientation before removing the old battery: the flat side with the plus marking faces up on nearly every watch, but check. Lift the retaining clip or spring bar with tweezers, slide the old cell out, and drop the new one in the same orientation. Do not touch the new cell's flat faces with bare fingers — grease shortens its life.

Check the watch ticks before you close it. If it does not, stop: the cell may be reversed, or the movement may have a different fault.

The gasket is the part that matters

Every caseback has a rubber or nylon gasket that provides the water seal. When you open the watch, that gasket is exposed. Before closing:

• Inspect the gasket for cracks, flattening or stretching. Replace it if in doubt — they cost very little.
• Wipe the seating channel clean; a single grain of grit can cause a leak.
• Apply a very thin film of silicone grease if you have it. Do not use household oil.

Then close the caseback evenly. On snap-backs, press around the edge progressively rather than at one point. On screw-backs, tighten by hand until firm, not until it will not turn.

When to pay someone instead

Take the watch to a jeweller if any of the following is true:

• It is rated for swimming or diving and you rely on that rating. A pressure test after closing is not something you can do at home.
• The caseback is a screw-down type with a fine thread, or the watch is a chronograph with pushers that need resealing.
• The watch is under warranty — opening it yourself usually voids the coverage.
• The movement shows corrosion or the old battery has leaked. Leaked electrolyte damages the circuit and needs cleaning, not just a new cell.

How often

A typical quartz cell lasts two to three years. Chronographs with multiple motors run through them faster, sometimes in 18 months. Changing the cell before it dies completely reduces the risk of leakage — if you notice the second hand starting to jump in two-second steps, that is the low-battery warning, and it is time.

If you would rather not open the case at all, any of the quartz watches in our men's or ladies' ranges can be serviced by a local jeweller for a modest fee, and all of them arrive with a two-year warranty. For mechanical watches, read automatic vs quartz.