What is a first cousin once removed?
A first cousin once removed is either your first cousin's child or your parent's first cousin. Both are one generation away from you, which is what "once removed" means.
- Shared ancestor
- 2 generations up from you
- They call you
- their first cousin once removed
- Average shared DNA
- ≈ 6.25%
- Cousin number · removed
- 1 · 1
Two people, one name
Look down: your first cousin's son or daughter is your first cousin once removed. Look up: your mother's or father's first cousin is also your first cousin once removed. The name works in both directions, so you and your parent's cousin call each other the same thing.
The tree above shows the younger version: your grandparents are their great-grandparents.
Why it is not "second cousin"
The cousin number comes from whichever person is closer to the shared ancestor. You are two generations below your grandparents, so the number is "first". The other person is three generations down, one more than you, so they are once removed. Their children and yours will be second cousins.
Shared DNA
About 6.25% on average, around 430 centimorgans in the Shared cM Project, with a wide real-world range of roughly 100 to 850 cM.
Check your own relative
Not sure this is the right term? Enter your actual connection.
Find the most recent ancestor you both descend from, then say how each of you is connected to them.
- They call you
- their first cousin once removed
- Expected shared DNA
- ≈ 6.25%
- Degree (civil / canon)
- 5 / 3
Why a first cousin once removed?
You share grandparents. You are 2 generations below them; the other person is 3 generations below them.
The cousin number comes from whoever is closer to the shared ancestor: 2 generations down, minus 1 = first cousin.
The gap between your two generation counts (3 − 2) is 1, so you are once removed.
Questions people ask
Is my mom's cousin my first cousin once removed?
Yes. Your mother's first cousin is your first cousin once removed.
What do my kids call my cousin?
Your cousin is their first cousin once removed, and your cousin's children are their second cousins.
Is it OK to just say "cousin"?
Of course. Most families do. The precise term matters mostly in genealogy, DNA matching and legal contexts.