Counting Cousins: How to Calculate Cousinhood – Family Tree

Are You My Cousin?

When it comes to ancestors things have a way of accelerating quickly from one generation one the next.  What starts as one person with two parents, becomes four grandparents, eight great grandparents, 16 great- great grandparents, and so on and so forth. At ten generations, a person has 2,046 ancestors. Each generation is twice the number of the generation that came before.

We have four basic types of blood relations: ancestors, siblings, aunts/uncles, and cousins.

Most of a person’s blood relatives are cousins. At any given time, most people will have thousands if not millions of cousins of varying degrees. First cousins, those who share the same set of grandparents will be the closest and share 12.5% of DNA. The more distant the connection, less shared DNA. Third cousins, who share a set of great-great grandparents, can expect to share less than 1% of DNA.

One thing I constantly struggle with when it comes to genealogy is determining how people are related. Even after decades of genealogy, I still use a cousin calculator for most extended relationships. The article below has a great explanation of how to calculate distant relationships.

How, exactly, are you related to the child of your great-great-grandmother’s sister’s son? We’ll explain the steps to calculating cousinhood.

Source: Counting Cousins: How to Calculate Cousinhood – Family Tree

Published by

Carrie Brown

Carrie Brown is a genetic genealogist, hobby blogger, and long-time history enthusiast with a passion for genealogical research. Currently she is working on her degree in business from Western Governors University. Carrie is a member of the International Society of Genetic Genealogy and volunteers her time as a research volunteer for

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