Cousin relationship calculator
Second cousin? Once removed? Tell us how the two of you connect and get the exact name, a tree you can show across the table, and what the other person should call you.
Find the most recent ancestor you both descend from, then say how each of you is connected to them.
- They call you
- their second cousin once removed
- Expected shared DNA
- ≈ 1.56%
- Degree (civil / canon)
- 7 / 4
Why a second cousin once removed?
You share great-grandparents. You are 3 generations below them; the other person is 4 generations below them.
The cousin number comes from whoever is closer to the shared ancestor: 3 generations down, minus 1 = second cousin.
The gap between your two generation counts (4 − 3) is 1, so you are once removed.
The lookups people make most
How the calculator names a relationship
Every blood relationship is really just two numbers. Walk up from yourself to the most recent ancestor you share with the other person and count the generations. Then walk down from that ancestor to them and count again.
- One count is zero? Then one of you is the other's direct ancestor: parent, grandparent, great-grandparent.
- One count is one? Then someone is a sibling of the other's ancestor: sibling, aunt or uncle, niece or nephew, and their "great-" versions.
- Both counts are two or more? You are cousins. Take the smaller count and subtract one to get the cousin number. The difference between the two counts is how many times "removed".
So if your great-grandparents (three up) are the other person's grandparents (two down), the smaller count is 2, giving first cousins, and the gap of 1 makes it first cousin once removed. The cousin chart lays every combination out on one grid, and the removed explainer lets you drag two people up and down a family line until the rule clicks.
A naming rule this tidy is really a small counting system hiding in plain sight. Watching an idea like that assemble itself step by step is what ahaboo does for things like the Moon's changing phases and photosynthesis, with narration over every move.
Three ways to enter it
Shared ancestor is quickest when you already know who links you ("her grandparents are my great-grandparents"). Step by step suits a chain you can recite: my dad, his sister, her son. Describe it takes a sentence like "my wife's cousin's daughter" and uses AI to turn it into steps; the name itself still comes from the rules above.
Your last few lookups stay in this browser only so you can jump back to them. Nothing is sent anywhere unless you use Describe it; see privacy.
Questions people ask
How do I work out how I am related to someone?
Find the most recent ancestor you both descend from. Count the generations from you up to that ancestor and from the ancestor down to the other person. If you are both two generations down, you are first cousins; both three down, second cousins. If the counts differ, the smaller count sets the cousin number and the difference is how many times removed.
What does "once removed" mean?
It means you and your cousin are one generation apart. Your parent's first cousin and your first cousin's child are both your first cousins once removed.
Is my cousin's child my second cousin?
No. Your cousin's child is your first cousin once removed. Your second cousins are the children of your parents' first cousins, which means your own child and your cousin's child are second cousins to each other.
Does the calculator work for in-laws and step-relatives?
Yes. In Step by step mode tick "Start from my spouse" for in-laws, or "End with that person's spouse" for relatives by marriage such as a step-parent or your cousin's husband.
Is the AI "Describe it" mode accurate?
AI only translates your sentence into a path of parent, sibling and child steps. The relationship name, tree and DNA figure are then calculated by fixed genealogy rules, and the page shows how it read your sentence so you can check it.