What is a fourth cousin?
Your fourth cousins share a great-great-great-grandparent with you — that is, a 3× great-grandparent. Each of you is five generations below that common ancestor. Fourth cousins are quite distant; you'll usually only discover them through detailed genealogy research or DNA matching.
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The calculator above is preloaded with this relationship. Change either person to work out any other connection, or open the full relationship calculator.
FAQs
Do fourth cousins share DNA?+
Fourth cousins share DNA only about half the time, because inheritance is random over so many generations.
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.
