What is my sister-in-law's brother to me?
That depends on how she became your sister-in-law. If she is your spouse's sister, her brother is your spouse's brother (or your spouse), which makes him your brother-in-law. If she married your brother, her brother is your brother's brother-in-law. He isn't your in-law, and English has no word for him.
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Brother's brother-in-law
English has no word for this person. The marriage that links you is your relative's, not yours, so they aren't your in-law, and families just say “brother's brother-in-law”.
- You
- Your brother
- His wife
- Her brother
From the other side, you are their sibling-in-law's sibling.
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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Know she's your brother's wife? Here's what her brother is to you.
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.
Related questions
FAQs
Is my sister-in-law's brother my brother-in-law?+
Only when she is your spouse's sister. When she is your brother's wife, her brother is family to your brother, not to you.
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.
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