The watch battery cross reference chart or also know as the button battery cross reference chart is easy to use. Find the brand of your battery, then follow it down your battery model. The equivalent battery will be at the beginning of that row. Click on the blue link to go to your battery options and purchase your replacement. For example, if you are looking for a watch battery replacement for your watch, and it was a Maxell SR626SW, you would scroll down the Maxell column until you found the part. Then at the beginning of the row you see what your SR626SW battery equivalent was a 377. The rows are highlighted across for easy reading.
PRO TIP: If you are having a hard time determining your battery, measure the width of the battery and then the height. Use the dimensions against the Dimensions column to find the battery that you need. You can also use a micrometer to measure the inside of a battery cavity to find out which battery you need.
Energizer