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Family relationship chart and guides

Each guide explains one relationship with an interactive ladder you can adjust. For any pair of relatives, the cousin calculator and its full cousin chart give the answer directly.

• What is a second cousin?Your second cousin is the grandchild of your grandparent's sibling. You share a set of great-grandparents, and both of you are three generations below them.
• What is a first cousin once removed?A first cousin once removed is a first cousin who sits one generation away from you. It works in both directions: your first cousin's child and your parent's first cousin are both your first cousins once removed.
• What does "once removed" mean?"Removed" tells you how many generations apart two cousins are. Once removed means one generation apart; twice removed means two.
• What is a third cousin?A third cousin shares a set of great-great-grandparents with you. Your parents are second cousins to each other, and your grandparents were first cousins.
• What is a second cousin once removed?Your second cousin once removed is either your second cousin's child or your parent's second cousin. The shared ancestor is your great-grandparent and their great-great-grandparent (or the other way round).
• What is a second cousin twice removed?A second cousin twice removed is your second cousin's grandchild, or your grandparent's second cousin. You are two generations apart.
• What is a great-aunt or great-uncle?Your great-aunt is your grandparent's sister, and your great-uncle is your grandparent's brother. The terms grand-aunt and grand-uncle mean exactly the same thing.
• What is a half cousin?Half first cousins share one grandparent instead of two, because their parents are half-siblings.
• What are double first cousins?Double first cousins share all four grandparents. It happens when a pair of siblings from one family marries a pair of siblings from another.
• What is a first cousin?Your first cousin is the child of your aunt or uncle. You share a set of grandparents, and you are both two generations below them.
• What is a first cousin twice removed?A first cousin twice removed sits two generations away from your first-cousin line: your first cousin's grandchild, or your grandparent's first cousin.
• What is a third cousin once removed?Your third cousin once removed is either your third cousin's child or your parent's third cousin. One of you is four generations below the shared ancestors, the other five.
• What is a fourth cousin?A fourth cousin shares a set of third-great-grandparents (great-great-great-grandparents) with you. Your parents are third cousins, and your grandparents were second cousins.
• What is a great-niece or great-nephew?Your great-niece or great-nephew is the child of your niece or nephew, which makes them your brother's or sister's grandchild.
• What is a step-cousin?A step-cousin is related to you through a step-parent: the child of your step-parent's sibling. You are cousins by marriage, with no shared ancestor.