Skyrim – walkthrough and progression.

And isn't there a built-in formula in the game, like in Heroes? That would be simpler. But of course, you can always share.

We still need to figure out how to count the days. I hope that, besides the names of the months, the calendar in Tamriel doesn't differ in any other way?

Yes, it seems everything is fine there; the year is indicated, and what it is divided into is clear from the name.