Cousin relationship calculator
Count how many generations each person is from the closest shared ancestor. The calculator turns those two numbers into a clear relationship.
How are two people related?
For each person, count the generations back to their closest shared ancestor.
No names or family records are requested or stored.
First cousins
Each side shows the number of generations back to the shared ancestor.
- Relationship
- Cousin degree
- 1
- Generations removed
- Same generation
Calculate a cousin relationship from a shared ancestor
Find the closest shared ancestor
Use the nearest ancestor both people have in common, not a more distant one from the same branch.
Count each side
A parent is one generation back, a grandparent is two, and a great-grandparent is three.
Read degree and removed
The shorter side determines cousin degree. The difference between both sides is the generations removed.
Common relationship examples
- 2 + 2 generations = first cousins
- 2 + 3 generations = first cousins once removed
- 3 + 3 generations = second cousins
Cousin calculator questions
What does once removed mean?
Removed describes a difference in generation. First cousins once removed are one generation apart.
Which shared ancestor should I use?
Use the closest shared ancestor. For first cousins this is a grandparent; for second cousins it is a great-grandparent.
Does the calculator save family information?
No. It uses only two generation counts. No names, dates, or family records are requested or stored.