Template:Age in years and days/doc

Use with caution on in-universe pages
Please note that this template, and really everything in category:age calculation templates should be 'used with caution on in-universe pages. They all assume that there is no year zero, which our in-universe rule on years does not. This is because there are several in-universe sources, not the least of which is the 1996 movie and its novelisation, which assume that there is a year zero. For ease of calculation, our in-universe time calculation templates, like timeline, are therefore based on a different principle than this one — namely, that year 0 does exist.

In practice, this means absolutely nothing to the calculation time of between two dates, so long as you're trying to figure out the distance between any two dates after 1/1/1 AD.