Forum Discussion
pre-1900 dates
I can find no help on how to tell Excel to properly format and calculate dates before 1900. I want to calculate age at death and have birth and death dates in columns. But Excel does not recognize ...
A very simple solution would be to just add an offset to both of the dates to be compared, so that a difference can then be calculated using the given Excel functions which start after 1900. 2000 years would include the repeating leap year dates, so should be a good value to offset.
Thus, 9/14/1752 12:00 am (date of Gregorian calendar acceptance) would be entered as 9/14/3752.
1/6/1980 12:00 am (0 time reference for GPS) would be entered as 1/6/3980.
The difference can then be calculated straightforward in Excel using the DAYS function, or just subtracting the earlier from the later date. (=83020 days, or 227.31x years at 365.24 days/yr).
