You can look in your owner's manual for the specific model and watch battery size. Other methods include doing a quick google search with the brand name and model number or opening up the watch to read the number on the battery. 116 and 377 are common watch battery types to look out for.
Can I use a 377 battery instead of 364?
No, despite they feature the same chemistry (silver-oxide) and very similar dimensions: - 364: 6.8 x 2.1 mm, - 377: 6.8 x 2.6 mm. Due to the same diameter and very similar height, it is possible to place 364 battery into the 377 battery compartment, and sometimes even vice versa.
What battery is equivalent to 364?
SR621SW
What type of batteries do watches use?
About Watch Batteries. Most batteries used in watches today are silver-oxide or lithium batteries, of which there are over 100 in use. The shelf life of a battery is the same as its useful life. Watches are so efficient that they use very little energy--compare this to getting 500 miles to the gallon in a car.