For several years I have been using the tables at this link:
https://en.wikipedia.org/wiki/List_of_battery_sizes

Most computer browsers allow control F for a search, you can quickly find your equivalent sizes with a search that way.

And another complicating factor is that some batteries come with different chemistry. For example, I have a watch that has about a dozen screws to open it up, and it takes four batteries. Thus, it takes a lot of time to change out the batteries in that watch. So I want the Silver batteries, not the Alkaline batteries. Costs a bit more but the longer lifespan of the batteries is worth it.