How To Figure Dates From Tombstones

Sun City Genealogist Vol. IV, No. 2 by Sun City Genealogical Society

Let us say you have found the tombstone of an ancestor and on that stone you find the date of his death and his age at death.  You want to determine the date of his death and his age at death.  You want to determine the date of his birth.  He died 16 April 1904.

1904  (year) 4 (months) 16 (days)
He was age 61 (years) 1 (month) 10 days
                   1843 (year) 3 (months) 6 (days) = 6 March 1843

But too often it is more complicated than that.  He died 16 April 1904.

        1904 (year)  4 (months) 16 (days)
His age was:    83 (years)       8 (months) 21 (days)

What you do is borrow 30 days from April for a total of 46 days-and borrow 12 months from 1904 for a total of 15 months, having already borrowed a month.  So you get:

         3. 1904 (year)    (3)   4  (months)  16 (days)
                                        + 12 (months)+ 30 days
             1903  (year)    - 15 (months)-    46 (days)
Age:         83 (years)       8 (months)     21  (days)
              1820 (year)         7 (months)     25 (days) or born 25 July 1820

To check this, say he was born 25 July 1820, and lived to the age of 83 years, 8 months and 21 days.  Put everything back that you have borrowed.

             1820 (year)       7 (months)   25 (days)
                 83 (years)     8 months      21 (days)
             1903  (year)    15 (months)   46 (days)
               +12 (months)-1 (month)  -  30 (days)
              1904  (year)    16 (months)  16 (days)
                                        12 (month
                                          4 (months)