Cousin Calculator
Work out exactly how you’re related to a relative. Tell us how many generations each of you is from your common ancestor, and the calculator reveals the cousin degree and removal.
Generations From Ancestor
Choose how many generations each person is below your shared ancestor
e.g. if the shared ancestor is your grandparent, you are 2 generations away.
Use the same shared ancestor as the reference point for both people.
Your Relationship
Cousin degree, removal, and shared DNA estimate
Choose how many generations you and your relative are from your common ancestor, then click Calculate Cousin Relationship.
Understanding Cousin Terminology
Cousin relationships are defined by two numbers: the “degree” (1st, 2nd, 3rd cousin) and how many times “removed” you are from each other.
Cousin Degree
The degree is the smaller of the two generation counts, minus one. Two grandchildren of the same person are 1st cousins; two great-grandchildren are 2nd cousins.
Times Removed
“Removed” is the difference between the two generation counts. A one-generation gap means “once removed”; a two-generation gap means “twice removed”.
Same Generation
If both people are the same number of generations from the ancestor, there’s no “removed” — you’re simply 1st, 2nd, or 3rd cousins with no removal.
Siblings & Direct Lines
If either person is 0 or 1 generation away while the other is further, the relationship may be a niece/nephew, aunt/uncle, or sibling rather than a cousin.
Cousin Relationship Chart
Cross-reference generations from the shared ancestor for both people to find the relationship instantly.
| Gen ↓ / Gen → | 2 (Grandchild) | 3 (Great-Grandchild) | 4 (2×Great) | 5 (3×Great) |
|---|---|---|---|---|
| 2 (Grandchild) | 1st Cousins | 1st, Once Removed | 1st, Twice Removed | 1st, 3× Removed |
| 3 (Great-Grandchild) | 1st, Once Removed | 2nd Cousins | 2nd, Once Removed | 2nd, Twice Removed |
| 4 (2×Great) | 1st, Twice Removed | 2nd, Once Removed | 3rd Cousins | 3rd, Once Removed |
| 5 (3×Great) | 1st, 3× Removed | 2nd, Twice Removed | 3rd, Once Removed | 4th Cousins |
Cousin Calculator FAQ
Everything you need to know about cousin degrees, removal, and how family relationships are defined.
A first cousin is someone who shares one set of grandparents with you. Your first cousins are the children of your aunts and uncles — that is, the children of your parents’ siblings.
‘Removed’ describes a generation gap between cousins. ‘Once removed’ means there is a one-generation difference between you and your cousin — for example, your first cousin’s child is your first cousin once removed, and your parent’s first cousin is also your first cousin once removed.
The cousin degree is determined by the smaller number of generations each person is from the shared ancestor, minus one. If both people are 2 generations from the common ancestor (i.e. grandchildren), they are second cousins. If both are 3 generations away, they are third cousins, and so on.
The number of times removed equals the difference between the two people’s generations from the shared ancestor. If one person is 2 generations from the ancestor and the other is 3 generations away, they are cousins once removed, because the generations differ by one.
Yes. Second cousins share a great-grandparent and are considered blood relatives, though the genetic relationship is more distant than that of first cousins, who share a grandparent.
A cousin (e.g. first cousin) is in the same generation as you relative to your shared ancestor. A cousin once removed is in a different generation — either one generation above you (like a parent’s cousin) or one generation below you (like a cousin’s child).