Relationship Calculator
Find the exact relationship and cousin degree between any two family members, with a visual path.
How many generations is Person 1 from the common ancestor?
How many generations is Person 2 from the common ancestor?
Understanding Generations
The "generation distance" is how many generations separate a person from their common ancestor. For example, your parent is 1 generation from your grandparent (their parent), while you are 2 generations from that same grandparent.
Cousin Degrees
Cousins share a common ancestor other than a parent. The "degree" of cousinship is determined by the closest common ancestor:
- 1st cousins share grandparents (2 generations)
- 2nd cousins share great-grandparents (3 generations)
- 3rd cousins share great-great-grandparents (4 generations)
"Removed" Relationships
When cousins are from different generations, they are "removed." The number of times removed equals the generational difference. For example, your first cousin's child is your first cousin once removed.
How to Calculate Genealogical Relationships
Understanding family relationships can be confusing, especially when dealing with cousins, great-aunts, or twice-removed relatives. This free genealogy relationship calculator helps you determine the exact relationship between any two people based on their common ancestor.
What is a Common Ancestor?
A common ancestor is the most recent person that two individuals both descend from. For siblings, this is their parent. For first cousins, it's their shared grandparent. The further back you go, the more distant the relationship becomes.
Understanding Cousin Degrees
The "degree" of cousinship depends on how many generations back your common ancestor is:
Share grandparents - both are 2 generations from the common ancestor
Share great-grandparents - both are 3 generations from the common ancestor
Share great-great-grandparents - both are 4 generations from the common ancestor
What Does "Removed" Mean?
When cousins are from different generations, the relationship is "removed." The number of times removed equals the generational difference between the two people. For example:
Your first cousin's child is your first cousin once removed
Your first cousin's grandchild is your first cousin twice removed
Your parent's first cousin is your first cousin once removed
Direct vs. Collateral Relationships
Family relationships fall into two categories:
- Direct relationships: Ancestors and descendants in a straight line (parents, grandparents, children, grandchildren)
- Collateral relationships: Related through a common ancestor but not in a direct line (siblings, cousins, aunts, uncles)
Why Use a Relationship Calculator?
Genealogists and family historians frequently need to determine relationships when:
- Building family trees and documenting connections
- Understanding DNA match relationships from testing services
- Writing family histories and explaining family dynamics
- Planning family reunions and determining how everyone is related
- Legal matters involving inheritance or family documentation
Common Genealogy Relationship Examples
Here are some frequently calculated relationships:
- Grandparent to Grandchild: Direct relationship, 2 generations apart
- Aunt/Uncle to Niece/Nephew: Collateral relationship, one person is 1 generation and the other is 2 generations from common ancestor (parent/grandparent)
- Great-aunt/Great-uncle: Similar to aunt/uncle but with an additional generation
- Half-siblings: Share one parent (special case not covered by this calculator)
Tips for Genealogy Research
When researching your family tree, understanding relationships helps you:
- Focus your search on the right ancestral lines and records
- Identify potential DNA matches and how you're related to them
- Organize your family tree software with accurate relationship labels
- Communicate clearly with other family researchers and distant relatives