How battery codes work
SR 626 SW
│ │ └ SW = low drain (most analogue watches) · W = high drain (watches with lights/alarms)
│ └ size: 6.8 mm diameter, 2.6 mm height (first digit(s) = diameter, last = height in tenths)
└ chemistry: SR = silver oxide (1.55 V) · LR = alkaline (1.5 V) · CR = lithium (3 V)
The three-digit numbers (377, 364, 371…) are the same cells under the numbering used by Renata, Energizer and others. AG numbers (AG4, AG13) are the cheaper alkaline equivalents.
Silver oxide or alkaline?
For quartz watches, use silver oxide (SR). It keeps a steady voltage until nearly empty and lasts much longer. Alkaline (AG/LR) cells of the same size fit but lose voltage gradually, which can make a watch run slow or stop early. Alkaline is fine for toys, calculators and cheap gadgets.
Changing the battery yourself
- Note which way up the old cell sat, and handle the new one with plastic tweezers — skin oil shortens battery life.
- Water-resistant watches need a new gasket and a pressure test to stay water-resistant. A shop can do this.
- Keep button cells away from children: a swallowed cell can cause serious internal burns within hours. Seek medical help immediately.
Questions people ask
Is 377 the same as 376?
Same size (SR626). 377 is the low-drain (SW) version and 376 the high-drain (W) version. Most analogue watches take 377; either works in most watches.
Is LR44 the same as SR44?
Same size, different chemistry. SR44 (357/303) is silver oxide and lasts longer; LR44 (AG13) is alkaline and cheaper.
Can I use a CR battery instead of SR?
No. CR cells are 3 V lithium and different sizes; they can damage a watch designed for 1.55 V.
Sources
Results are estimates to help you plan. Always confirm important numbers with the seller, carrier or authority concerned. Last reviewed: November 2026.