Relationship Finder

What is my cousin's daughter to me?

Your cousin's daughter is your first cousin once removed, and you are her first cousin once removed too.

6.25% shared DNA on average. Real amounts vary.

Diagram: how your cousin's daughter is related to youYouParentGrandparentscommon ancestorsAunt/uncleFirst cousinFirst cousin onceremovedthem

you them common ancestors double line: marriage

The usual guesses, “niece” and “second cousin”, are both wrong. Your cousin's daughter is one generation below you, so she is your first cousin once removed. The same goes for your cousin's son.

She is not your niece: nieces and nephews are your siblings' (or your spouse's siblings') children. She is not your second cousin either. She is a second cousin to your children, because they are the same generation.

How we worked it out

Follow the chain one step at a time:

  1. Your cousin: first cousin (2 up, 2 down)
  2. Your cousin's daughter: first cousin once removed (2 up, 3 down)

Your grandparents are her great-grandparents: they are your common ancestors.

She is one generation below you.

Count the generations to your common ancestors: 2 up from you, 3 down to her. The cousin number is one less than the smaller count (2), so first cousin. The counts differ by 1, so once removed.

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    Related questions

    Is my cousin's daughter my niece?
    No. A niece is your sibling's daughter. Your cousin's daughter is your first cousin once removed, although many families casually call her a niece and have her call you aunt or uncle.
    What does my cousin's daughter call me?
    You are her first cousin once removed too; the term works both ways. Most people just say “cousin”.
    What is my cousin's daughter to my son or daughter?
    Your children and your cousin's children are second cousins: they share great-grandparents.

    More family relationship answers