What Does "Once Removed" Mean? Cousins Explained with a Chart

In a family tree, "once removed" means that two cousins belong to generations one step apart. Your first cousin's child is your first cousin once removed, and so is your parent's first cousin. "Twice removed" means two generations apart. The number before "cousin" (first, second, third) tells you how far back your shared ancestor is; the word "removed" tells you how many generations separate you.

First, second and third cousins

A cousin is a relative who shares an ancestor with you but is not your direct ancestor, descendant, sibling, aunt, uncle, niece or nephew. The number in front of "cousin" depends on which ancestor you share.

• First cousins share grandparents. Your first cousin is the child of your parent's brother or sister.
• Second cousins share great-grandparents. Your parent and your second cousin's parent are first cousins to each other.
• Third cousins share great-great-grandparents.
• Fourth cousins share third-great-grandparents, and so on, one more "great" each time.

A quick way to remember it: the number of the cousin is one less than the number of generations between each person and the shared ancestor. Grandparents are two generations up, so their grandchildren are first cousins. Great-grandparents are three generations up, so their great-grandchildren are second cousins.

What "removed" means

Cousins of the same degree are always in the same generation. When two cousins are in different generations, the gap is counted as "removed." The FamilySearch genealogy blog puts it simply: the number before "removed" is the number of generations between the two people.

That means a first cousin once removed can be either of two people:

• the child of your first cousin (one generation below you), or
• the first cousin of one of your parents (one generation above you).

The relationship works both ways. If Rosa is your first cousin once removed because she is your mother's cousin, then you are Rosa's first cousin once removed too. The term does not tell you who is older, only that you sit in different generations.

How to work out any cousin relationship

1. Find the most recent common ancestor you both descend from: a shared grandparent, great-grandparent and so on.
2. Count the generations from that ancestor down to each of you. A child is 1, a grandchild 2, a great-grandchild 3.
3. Take the smaller number and subtract one. That gives the degree of cousin: first, second, third.
4. Subtract the smaller number from the larger. That is how many times removed. If the numbers are equal, you are not removed at all.

Cousin relationship chart

Read across from one person's position and down from the other's. Each position is counted from the common ancestor.

Common ancestor's…	Child	Grandchild	Great-grandchild	2nd great-grandchild
Child	Sibling	Niece or nephew	Grandniece or grandnephew	Great-grandniece or great-grandnephew
Grandchild	Niece or nephew	First cousin	First cousin once removed	First cousin twice removed
Great-grandchild	Grandniece or grandnephew	First cousin once removed	Second cousin	Second cousin once removed
2nd great-grandchild	Great-grandniece or great-grandnephew	First cousin twice removed	Second cousin once removed	Third cousin

The pattern continues outward: every step down the diagonal adds one to the cousin number, and every step away from the diagonal adds one "removed."

Worked examples

Your cousin's daughter

You and your cousin Ben share grandparents, so you are each two generations below them. Ben's daughter Ivy is three generations below them. The smaller count is 2, so you are first cousins; the difference is 1, so Ivy is your first cousin once removed.

Your mother's cousin

Your mother and her cousin Carl share grandparents, who are your great-grandparents. Carl is two generations below them and you are three. Again the smaller count is 2 and the difference is 1, so Carl is your first cousin once removed.

Your child and your cousin's child

Both children are three generations below the shared grandparents. The counts are equal, so there is no "removed": they are second cousins. Many families call them "first cousins once removed" by mistake, but that name belongs to the cross-generation pairs above.

Your grandfather's cousin

Your grandfather and his cousin share grandparents, who are your second great-grandparents. His cousin is two generations below them and you are four. The smaller count is 2 and the difference is 2, so he is your first cousin twice removed.

A famous example

Queen Elizabeth II and Prince Philip were third cousins through Queen Victoria: each was a great-great-grandchild of hers. You can see the lines in our Queen Victoria family tree.

Double cousins and half cousins

Double cousins

Double cousins are related through two branches of the family at once. It happens when two siblings from one family marry two siblings from another, for example two brothers marrying two sisters. Their children are double first cousins: they share both sets of grandparents instead of one.

Half cousins

Half cousins descend from half siblings, so they share one grandparent instead of a grandparent couple. If your father and your cousin's mother had the same father but different mothers, you and your cousin are half first cousins. In a family tree, it helps to write "half" in the label so later readers understand why only one grandparent appears.

Tips for labeling cousins in your tree

• Always identify the common ancestor first. Most mistakes come from guessing the relationship from ages.
• Do not assume age tells you the generation. In large families, an uncle can be younger than his nephew, and a "removed" cousin can be your age.
• Use the chart above, or the relationship calculator in family tree software, as a check.
• When writing family history for other readers, name the link in plain words as well: "my mother's cousin" is clearer than the formal term alone.

If you are just starting to map relatives, see our step-by-step guide on how to make a family tree.