Age / Date calculator
I do not know the birth year of my 9th great grandmother. But I do have records of the birth of her children. From that I can approximate her birth year.
If we assume that she would be no younger than age 15 at the birth of her first child, and no older than age 45 at the birth of her last child, we could approximate accordingly:
Birth year of the youngest child: 1674 (1674 - 15 = 1659)
Birth year of the oldest child: 1683 (1683 - 45 = 1638)
The mother’s birth year is very likely between 1638 and 1659
It would be great if Family Search had such a calculator built in. This could be used to narrow a search and validate existing information.