Tuesday, June 5, 2012

Cemetery Math - Date of Birth Calculator

Aged 51 Yrs, 2 Mos, & 26 Days
Who in the world came up with placing only a date of death on a headstone followed by "Aged X Years, Y Months, Z Days"? (See photo example.)  If "normal" math scares you, this is truly a nightmare when it comes to trying to figure out a date of birth by subtracting months, days, and years!  If they could figure out that information, they must have known the date of birth to start with.  It would seem logical to use the date of birth and death as we're accustomed to seeing today, especially on older stones when literacy rates and mathematical skills were likely to be less than proficient.  Even today, who is carrying around scratchpads to work on deciphering the dates?  This is one fad I'm glad that's over!

Well, I have found a wonderful way to help easily solve this mathematical problem.  ProGenealogist.com has a great tool that is easy to use for this very purpose, appropriately named the Birth Date Calculator.  One of the best features about it is it's FREE!

Approximating the date of birth is possible but I am always leery of possible errors that can creep in.  For example, some stones were not erected for months or maybe even until years after death.  Memory doesn't always prove to be accurate when the time comes to actually place the stone.  I hope everyone finds this tool useful in their research!


  1. Hi
    how about birth calculator without death date:
    This is a brainbuster:
    A man is recorded age 24 on 27 March 1632 and
    he is recorded age 29 on 26 August 1636.
    When was he born?
    The Board for Certification of Genealogists gives an example, saying the a whole year must be allowed for his birthdate say 27 March 1608 to earliest 28 March 1607. But how does that connect to the 1636 date?
    My answer is He was born between ab. 26/27 March 1607 and 26/27/ August 1607.


  2. I think you would need to consider the sources first. Is it possible someone other than the individual was supplying the information? People rarely age 10 years on the US Census partly because someone else (maybe a neighbor or even a child) supplied the answers and they guessed. Other times, a false date is given when there is an age requirement, such as entering military service or the age of consent for getting married and so the "new" date ends up being used to perpetuate the lie.
    Aside from finding another source to corroborate the individual's age, I think you're stuck with your best guess of "between March and August" which really is a short time frame considering this was over four centuries ago and that the records still exist allowing you to get that close. I think you can cite both dates (or the "between" dates) and note your reasoning for your conclusion and it will be acceptable though not perfect.
    I hope this helps.