Cousin Relationship Calculator
Have you ever wondered how you’re related to a distant family member? Terms like “second cousin once removed” can sound confusing. Luckily, the Cousin Calculator on this page makes it easy to understand family connections by determining your exact relationship to another person based on how many generations each of you are from a shared ancestor.
Whether you’re building a family tree, working on genealogy research, or simply curious about how you’re related to someone, this tool helps you decode the complex world of cousin relationships in just seconds.
What Is the Cousin Calculator?
The Cousin Calculator is a family relationship tool that determines how two individuals are related by identifying the generational gap between each person and their most recent common ancestor. It classifies relationships such as:
- Siblings
- Aunt/Uncle & Niece/Nephew
- First, second, third cousins
- Removed cousins (e.g., “first cousin once removed”)
This tool uses clear logic to return both a relationship title and an explanation of how the connection is determined.
How to Use the Cousin Calculator – Step-by-Step
Using the calculator is simple. Here’s how to get started:
- Enter Generations from Person 1 to the Common Ancestor:
This means how many generations separate Person 1 from the shared ancestor (e.g., their grandparent is 2 generations up). - Enter Generations from Person 2 to the Same Common Ancestor:
Repeat this for Person 2. You can use the same number if both people are equally distant. - Click “Calculate”:
The tool will instantly return the specific relationship between the two individuals. - View the Results:
You’ll see a relationship label (like “Second Cousins Once Removed”) and a brief explanation that breaks it down in plain language. - Optional – Click “Reset”:
If you’d like to try again with different values, just click the Reset button to clear the fields.
Example: How Are These Two People Related?
Example 1:
- Person 1 is 3 generations from the common ancestor (great-grandchild)
- Person 2 is 3 generations from the same ancestor (great-grandchild)
Result:
Second Cousins – They share a great-grandparent and are the same generational distance from that ancestor.
Example 2:
- Person 1 is 2 generations from the common ancestor
- Person 2 is 4 generations away
Result:
First Cousins Twice Removed – One person is a grandchild of the common ancestor, the other is a great-great-grandchild. The two-generation gap is described as “twice removed.”
Example 3:
- Person 1 is 1 generation away
- Person 2 is 3 generations away
Result:
Great-Aunt/Uncle – Person 1 is the great-aunt/uncle of Person 2.
Why Understanding Cousin Relationships Matters
Understanding how you’re related to someone isn’t just fun—it’s also useful for:
- Genealogy Research: Accurately label distant relatives in family trees.
- DNA Testing Sites: Interpret results from services like AncestryDNA or 23andMe.
- Family Reunions: Figure out how everyone fits together.
- Legal & Inheritance Matters: Relationship proximity can affect inheritance rights in some jurisdictions.
- History Projects or Cultural Studies: Understanding family ties across generations provides cultural context and historical insight.
Frequently Asked Questions (FAQs)
1. What does “removed” mean in cousin relationships?
“Removed” indicates a difference in generations. For example, if your cousin’s child is one generation below you, they are your “first cousin once removed.”
2. What is a second cousin?
Second cousins share the same great-grandparents but not the same grandparents.
3. What is a first cousin once removed?
This means one person is the child of the other’s first cousin—or vice versa.
4. Can someone be both a cousin and an aunt/uncle?
Biologically, no. But blended families and close family friendships sometimes use terms interchangeably.
5. How many generations are between me and my great-grandparent?
Three generations: you → parent → grandparent → great-grandparent.
6. What are siblings in terms of generations?
Siblings are each one generation from their common ancestor (their parent).
7. How does the calculator determine the cousin “degree”?
It’s based on the person who is closer to the common ancestor. Subtract one from the lower number of generations to determine the cousin level (e.g., 2 → first cousins).
8. How does it calculate “removed”?
The number of times “removed” equals the difference between the two generations.
9. Can the tool detect half-cousins or half-siblings?
No, it assumes full biological connections based on shared ancestors.
10. Does it work for ancestors beyond great-great-grandparents?
Yes. You can input any number of generations to the common ancestor.
11. How is a “great-aunt” determined?
If Person 1 is one generation from the ancestor, and Person 2 is multiple generations down, Person 1 becomes a (great-)aunt or uncle.
12. Can I use this for non-biological relationships (e.g., step-family)?
Not accurately. This calculator is designed for blood-related relationships.
13. What if both people are many generations apart from the ancestor?
The tool still works by applying the cousin degree/removal formula.
14. What’s the difference between second cousins and first cousins once removed?
Second cousins share the same great-grandparents. First cousins once removed have a one-generation difference between them.
15. Is the calculator accurate for large generational gaps (e.g., 6 vs 2 generations)?
Yes, the math works the same. The cousin degree is still based on the smaller number minus one.
16. Why is it important to know your degree of cousinship?
It can clarify genetic relationships, legal family ties, and help accurately build family trees.
17. Can I use this tool for genealogy software or projects?
Yes. It can help you label relationships correctly when charting ancestral trees.
18. Do both people have to be living for this to work?
No. The calculator only requires generational distance from a common ancestor, regardless of whether the individuals are living or deceased.
19. Can this help me understand DNA match predictions?
Yes. If you know how many generations apart you and a match are from a shared ancestor, this tool can clarify the cousin label.
20. What if both people are five generations from the ancestor?
They would be fourth cousins, because the cousin degree is one less than the shared generational distance.
Final Thoughts
Genealogy can feel overwhelming, especially when cousin relationships become complex. But with this Cousin Calculator, you no longer need to guess. By entering just two numbers—your and your relative’s generational distance from a common ancestor—you’ll get an instant, clear explanation of your relationship.
Whether you’re mapping out a family tree, exploring ancestry DNA connections, or just trying to figure out how your distant cousin is related to you, this tool is accurate, fast, and easy to use.
Try it now and unlock your family connections—one generation at a time.