Want to be the most popular person at your next family gathering? Be the person who can explain the difference between “second cousins, once removed” and “third cousins, twice removed” and your relatives will look on you like you’re a genius, an oracle, an armchair genealogist to whom they’re proud to be bound by blood. Here’s how to figure out how closely related you are to all your cousins.


The handy chart above makes the relationships pretty simple to determine.

Flowing Data explains how the chart works:

Figure out the common ancestor between two relatives. Then select the relationship of the first relative to the common ancestor in the top row. Move down to the row that corresponds to the relationship of the second person to the common ancestor. The result is the relationship of the second person to the first.


Or, if you prefer, here’s a handy glossary of cousin terms.

Cousins

Your cousins are people with whom you share a common ancestor, and the most recent common ancestor you share is at least two generations away. That distinguishes them from, say, your siblings, who are the people with whom you share common ancestors that are one generation away—those common ancestors are your parents.

First cousins

Your first cousins are the children of your aunts and uncles. First cousins share a grandparent (i.e., your grandparents are two generations away from both you and your first cousins).


Second cousins

Second cousins share a great-grandparent and are the children of first cousins. So the kids of your dad’s first cousin are your second cousins.


Third cousins

Third cousins share a great-great-grandparent and are the children of second cousins. The kids of your dad’s second cousin are your third cousins. Are you sensing a pattern here? Fourth cousins share a great-great-great-grandparent and so on.


Once removed

If you’re “removed” from a cousin, that means you’re from different generations. If you’re “once removed” from a cousin, that means you are separated by one generation. Your dad’s first cousin is your first cousin, once removed. Your first cousin’s daughter is also your first cousin, once removed.


Twice removed

If you’re “twice removed” from a cousin, you are separated by two generations. Your grandmother’s first cousin is your first cousin, twice removed. The granddaughter of your first cousin is also your first cousin, twice removed.


This article was originally published on 11/22/14 and was updated on 5/17/19 to include clearer and more thorough information.