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).
Preset to this relationship. Change the steps to compare with neighbouring relationships.
They are your
second cousin once removed
Common ancestors: your great-grandparents. Expected shared DNA: 1.56%
Shorter branch = 3 steps → 3 − 1 = 2 → second cousin. Branches differ by 1 → once removed.
Expected shared DNA is about 1.56% (1/64).
The relationship is the same in both directions: if your mother's second cousin is your second cousin once removed, you are theirs as well.
Your own children and your second cousin's children are third cousins to each other.
To check a real pair of relatives, add them to the family tree maker and use How related?, or look them up on the cousin chart.
Questions
What is my mom's second cousin to me?
Your second cousin once removed.
What is my second cousin's son to me?
Your second cousin once removed.