Western History & Genealogy Blog


Eat! Learn! Celebrate!

Colorado Genealogical Society celebrates 85 years of service to the genealogical community. 

Founded in 1924, the Colorado Genealogical Society welcomes visitors and new members who want to share their  interest in family history and genealogical research.

Tombstone Math

Here's a shortcut for calculating a birth date when the death date is given on the tombstone or in an obituary, but only the age in years, months and days.

It is called the 8870 formula.

Here's how to use the "magic" 8870 formula.

Here's an example: Ancestor died May 6, 1889 at the age of 71 years, 7 months and 9 days, convert those to numbers