What is a first cousin once removed?

When I was growing up, I was told that my paternal grandparents were second cousins. But when I asked exactly how they were related, no one really knew. To them, a second cousin simply meant being more distantly related than a first cousin.

Years later I began researching my family history and I discovered the relationship between my grandparents. What I found was that my grandparents were not second cousins, but actually first cousins once removed.

So what is a first cousin once removed? Or in another way of asking . . .

What is consanguinity?

Consanguinity is a term used by genealogists to indicate a family relationship between two people. In other words, the two people share a kinship in that they both descend from a common ancestor.

Terms like grandfather, aunt, cousin, and cousins removed are all used to state the degree of consanguinity or kinship between two people.

About Family Relationships

So how do we determine the family relationship between two cousins who share a common ancestor?

First you need to determine to what degree they are cousins (see fig. 1). Are they second cousins, third cousins, or even seventh cousins?

You determine this by moving down both paths of lineal descent from the common ancestor an equal number of generations until you reach the first of your target relatives.

Consanguinity Chart Example

Starting with the grandchildren being first cousins, each succeeding generation is said to be second cousins, third cousins, and so on.

If both relatives are an equal distance from the common ancestor, that is to say, they are the same number of generations down from the common ancestor, then you are done and you have your answer.

What does once removed mean?

But what if the two relatives are not an equal distance from the common ancestor and one is further down the family tree? This is where the term removed comes in.

For each generation that one relative descends further down the family tree than the other, this is counted as once removed, twice removed, etc (see fig. 2). You may also see it stated as one time removed, two times removed, and so on. Or it might be abbreviated where 2C1R is the same as second cousin once removed and 3C4R is third cousin four times removed.

Fig. 2
Consanguinity Chart Example

Free Chart Helps Calculate Family Relationships

If all this still seems a little bit confusing, then you might want to download the following relationship chart to help simplify the whole process. Just click on the link below to bring up the chart, and then save or print it to your computer.