What is my father-in-law's father to me?
Your father-in-law's father is your grandfather-in-law — informally, since English stops issuing formal in-law titles after the parent generation. He is your spouse's grandfather, and most people describe him exactly that way. The tie runs through your marriage; no blood connects the two of you.
Relationship
Grandfather-in-law
English has no single formal word for this relative — “grandfather-in-law” is the label genealogists use.
- You
- Your father-in-law
- His father
From the other side, you are their grandchild-in-law.
This connection runs through a marriage, not a shared ancestor, so the ancestor chart can't draw it.
The calculator below works out blood relationships through a shared ancestor — use it to explore the rest of your tree.
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This relationship sits outside the shared-ancestor model, so the card above carries the answer and the calculator opens in its default state. Work out any blood relationship with it, or open the full relationship calculator.
FAQs
What would my father-in-law's father be to me?+
Your grandfather-in-law, informally — or simply 'my spouse's grandfather.' English has no formal title here.
Who am I to my father-in-law's father?+
You are his grandchild-in-law — informally again; formally, a grandchild's spouse.
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.
