User:BobC/Determining Unknown Birthdates

Determining Unknown Birthdates

There is a process called Formula or Rule 8870 that enables one to determine the date of birth if only the age and date of death are known. Using this Formula 8870 is a tremendous help to ascertain a birth date. In order to arrive at the birth date you only have to use the formula to quickly get the date of birth rather than try to count backward.

For instance, if a tombstone records that a person died on May 6, 1889, and was 71 years, 7 months and 9 days old, this is a quick way to establish the date of birth:

YEAR/MONTH/DAY

If the age in months and the age in days are less than the month and day in the date of death, you can just subtract directly. I can give you an example that I know is correct.

Date of death - 1879 September 25

Age at death - 83 yrs., 1 mo, 5 days

Subtract 83 from 1879 = 1796

Subtract 1 from 9 = 8

Subtract 5 from 25 = 20

Result = 1796 August 20, the date of birth

Source: Article by Cynthia Rhoades, Director of Genealogy, The Harlan Family in America