What is a third cousin?
Your third cousins share a great-great-grandparent with you. Each of you is four generations below that common ancestor, and your great-grandparents were siblings. Third cousins are distant enough that many people never meet them, though DNA tests often reveal them.
Loading tool…
The calculator above is preloaded with this relationship. Change either person to work out any other connection, or open the full relationship calculator.
FAQs
How are third cousins related?+
Third cousins descend from a shared great-great-grandparent; their great-grandparents were siblings.
Does the calculator store my family details?+
No — it runs entirely in your browser. Nothing you enter is uploaded or saved on our servers.
Start with one relative and see what comes back.
Add what you remember and AncestorIQ searches for the rest. Free to build your tree for as long as you like.
No credit card needed. Your tree stays yours.
