Cousins

What is a third cousin once removed?

A third cousin once removed is a third cousin from a different generation: your third cousin's child, or your parent's third cousin.

The shared ancestors are great-great-grandparents to one of you and great-great-great-grandparents to the other: 4 generations down on one side, 5 on the other.

Two ways to be one

Your third cousin's child is your third cousin once removed.
Your parent's third cousin is also your third cousin once removed.

How to work it out

Find the ancestors you share and count the generations from them down to each of you: 4 and 5.
The smaller number minus one gives the cousin degree: 4 minus 1 is 3, so "third".
The difference between the two numbers is how many times "removed": 5 minus 4 is 1, so "once removed".

The third cousin once removed square is marked. Rows are you, columns your relative.

You are the ancestor's…	Child	Grandchild	Great-grandchild	2x great-grandchild	3x great-grandchild	4x great-grandchild
Child	Sibling	Niece or nephew	Grandniece or grandnephew	Great-grandniece or nephew	Great-great-grandniece or nephew	Great-great-great-grandniece or nephew
Grandchild	Aunt or uncle	First cousin	First cousin once removed	First cousin twice removed	First cousin three times removed	First cousin four times removed
Great-grandchild	Great-aunt or uncle	First cousin once removed	Second cousin	Second cousin once removed	Second cousin twice removed	Second cousin three times removed
2x great-grandchild	Great-great-aunt or uncle	First cousin twice removed	Second cousin once removed	Third cousin	Third cousin once removed	Third cousin twice removed
3x great-grandchild	Great-great-great-aunt or uncle	First cousin three times removed	Second cousin twice removed	Third cousin once removed	Fourth cousin	Fourth cousin once removed
4x great-grandchild	Great-great-great-great-aunt or uncle	First cousin four times removed	Second cousin three times removed	Third cousin twice removed	Fourth cousin once removed	Fifth cousin

Check it in the cousin calculator