Watch Battery Replacement Guide
Find the right button cell for your watch and replace it yourself in minutes.
Almost every quartz watch runs on a single button cell. The number stamped on the old battery — 377, 364, 371 or an SR number — is the only reference you need. Match it, then buy.
- 01Read the old battery
The stamped number is the model. If it is worn, check the inside of the case back instead.
- 02Check the case back
Many watches print the battery type under the back cover or in the side sticker.
- 03Measure the diameter
A calliper or ruler across the cell confirms the size class (6.8 mm, 9.5 mm, 11.6 mm…).
Open the case back
Use the right tool: a case knife or a round wrench. Watch for the tiny notch — never pry on the glass.
Pry the old cell out
Each case back fits a specific battery size. Pry gently with a plastic pick, not a metal screwdriver.
Insert the new battery
Positive polarity (the side printed with +) faces up in almost every watch — match the old cell’s orientation.
Close and test
Snap the back on and confirm the watch is running before sealing.
FAQ
What battery does my watch take?
Whatever is stamped on the old cell or inside the case back — usually a 377, 371, 364 or an SR silver-oxide number.
How long does a watch battery last?
One to three years for a silver-oxide cell, depending on features and backlight usage.
Is 377 the same as SR626SW?
Yes — 377, SR626SW and AG4 are the same 6.8 × 2.6 mm silver-oxide cell.
Can I replace the battery myself?
Yes, with a case-back tool and a plastic pick — four steps, no soldering.
Why does my watch battery die fast?
Usually a dim backlight or a stuck alarm. Silver-oxide cells last longer than alkaline equivalents.