Date/Age Calculator

It seems that many times when the age was given on headstones, in obituaries, etc
it was calculated by always assigning 30 days to a month as well as not taking into
account leap years. This calculation uses the actual days in each month and accounts
for leap years, so the result here may not agree with what is shown elsewhere.


Check here to take into account the change in calendar from Julian to Gregorian (it was
changed at different times in different parts of the world; this calculation will use
the time it was changed in the Kingdom of Great Britain and some of it's colonies, one being America).
This means, for example, that a person born on 1 Sep 1752 and dieing on 15 Sep 1752 will be 3 days old
at the time of death. (2 Sep 1752 was followed by 14 Sep 1752 with the change in calendars.)
Also, using the Julian Calendar, the year began on 25 Mar. However, for this calculation and display, the year
will always start with 1 Jan.

Fill in 2 unknowns (either 2 dates, or 1 date and the age) and the third unknown will be calculated.