Calendar Functions for dates starting in 1582

[Matt Agajanian]

Hi. Thanks for the User Solutions Calendars link.

Quite useful. Although the date +/- days works with March 1, 1901-Feb 28, 2100, I need to calculate future/past dates starting with 1582. I’ve tried to simply add the amount of days plus/minus to the generated Julian/Gregorian Date Number, but that doesn’t work.

Could you help me with that, please?

I found this on the web, but it doesn’t include date arithmetic formulas.
Julian/Gregorian Date Numbers

Thanks