Second Cousin Once Removed
See who a second cousin once removed is, drawn as a family diagram, and swap the viewpoint to see it from their side. Change degree and removal for any other cousin.
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How to find out who is your 2nd cousin once removed
- Read the heading “Your 2nd cousin once removed” and the sentence under it. It names who the relative is in words.
- Press a chip such as “2nd cousin twice removed” to jump to another relationship.
- Or set “Cousin degree” (1st to 10th) and “Times removed” (0 to 10) yourself.
- Under “Who is younger?” choose whether they are younger than you or older than you. With 0 times removed, both of you are in the same generation.
- Press “Swap viewpoint” to see the relationship from their side. The tiles “Seen from you” and “Seen from them” give the wording for each of you.
- Under “Shared ancestors” choose “One person (half cousins)” if you share only one ancestor.
- Look at the family diagram. It shows the common ancestors at the top, your line on the left and their line on the right.
- Read “Generations from the common ancestor” and “Expected shared DNA” for the numbers behind the name.
- Read the line under the diagram. It says how many generations you and they are below the shared ancestor and which person in the diagram is the cousin.
- Press a neighbouring chip, for example the next degree or one more removal, and watch the two generation numbers and the DNA figure change.
- Press “Copy link to this result” to share the exact relationship.
What is a second cousin once removed?
Your second cousins are people who share a great-grandparent with you and are in your own generation. This relationship is one generation away from that. The person is either the child of your second cousin or the second cousin of your parent. In the default diagram you are 3 generations below the shared great-grandparents and the other person is 4 generations below them.
What does “once removed” mean?
“Removed” counts generations. Once removed means one generation up or down. The degree, 2nd, stays the same, and only the generation of one person changes. The name is the same for both people: they are your second cousin once removed and you are theirs.
How many generations separate you and a second cousin once removed?
You are 3 generations below the shared ancestor and they are 4, or the other way round. The smaller number minus one is the cousin degree (3 - 1 = 2), and the difference between the numbers is the removal (4 - 3 = 1). The ancestors you share are your great-grandparents and their great-great-grandparents.
How much DNA does a second cousin once removed share?
For full relatives the average expectation is (1/2) to the power of the two generation numbers added together, minus one. For 3 and 4 that is (1/2)^6, which is 1/64 or 1.5625%. If only one ancestor is shared instead of a couple, the figure is halved to 0.78125%. These are averages over many pairs, and real amounts differ from pair to pair.
How does it compare with nearby relationships?
| Relationship | Generations (you and them) | Expected shared DNA |
|---|---|---|
| 1st cousin twice removed | 2 and 4 | 3.125% (1/32) |
| 2nd cousin | 3 and 3 | 3.125% (1/32) |
| 2nd cousin once removed | 3 and 4 | 1.5625% (1/64) |
| 2nd cousin twice removed | 3 and 5 | 0.78125% (1/128) |
| 3rd cousin | 4 and 4 | 0.78125% (1/128) |
| 3rd cousin once removed | 4 and 5 | 0.39063% (1/256) |
The table shows why DNA alone cannot name a relationship: a 2nd cousin and a 1st cousin twice removed average the same, and so do a 2nd cousin twice removed and a 3rd cousin. The cousin chart lists every combination.
How can I work it out without the page?
Count the generations from you up to the nearest common ancestor, and the same for them. The smaller count minus one is the degree, and the difference between the counts is the number of times removed.
Frequently asked questions
Is a second cousin once removed blood related?
Yes. You descend from the same great-grandparents or, for the older person, great-great-grandparents. A person who is only related by marriage, such as the spouse of a second cousin, is not.
What is the difference between a cousin once removed and a second cousin?
A first cousin once removed shares a grandparent with one of you and is a generation away from your own. A second cousin shares great-grandparents with you and is in your generation. The number in front of “cousin” says how far back the shared ancestor is; “removed” says how many generations apart the two people are.
Is a 3rd cousin the same as a 2nd cousin once removed?
No. A third cousin shares a great-great-grandparent with you and is in your generation (4 and 4). A second cousin once removed shares a great-grandparent with one of you (3 and 4). The second is slightly closer: about 1.5625% expected DNA against 0.78125%.
Can a second cousin once removed be the same age as me?
Yes. Generation is not age. A second cousin once removed can be older or younger than you in years, whichever generation they belong to.
Who is a second cousin twice removed?
Your second cousin’s grandchild, or your grandparent’s second cousin. Press the chip “2nd cousin twice removed” to see it with a diagram.
Does this upload my information?
No. Only the numbers you choose are used, and they stay in your browser.
- First Cousin Once Removed: the closer relationship, explained from both sides.
- Third Cousin: meaning, chart and DNA of a third cousin.
- Cousin Calculator: work from the common ancestor to the name.
- Cousin Chart: all cousin degrees and removals in one table.
- Relationship Calculator: relationships between two people in a tree.
- Relationship Chart: the chart of family relationships.
- Inbreeding Coefficient Calculator: how related two parents are.
- Kinship Terms: relationship words in other languages.
- How Many Ancestors Calculator: ancestors per generation.
- Gedcom Viewer: open a family tree file.