Which nth cousin are you, and are you removed?

Time I got to grips with how cousin numbers work, so I’ve been studying it on various online resources. This is how I find it easiest to work out.

– Find the nearest common ancestor, going back in time, for you and your cousin.
– Count how many generations there are between that ancestor and yourself (but NOT counting either the ancestor or yourself).
– Do the same for your cousin.
– If you both have the same number of generations going back to the common ancestor then you are xth cousins, x being the number of generations going back.
– If you are not the same number of generations then you are cousins removed. Take the number of generations between whoever is closest to the common ancestor, and add once removed, twice removed, etc. for how many generations separate you and your cousin.

So anyone descended from Thomas Strachan and Susannah Alexander (my gggg grandparents) and who is of the same generation as myself is my 5th cousin. Anyone descended from them but a generation further down the tree would be my 5th cousin once removed.

Doing a chart helps. Here’s how I’m related to Cathy:
Common ancestors John Strachan and Agnes Neilson
Gen 1 – siblings Robert Strachan and Samuel Strachan
Gen 2 – 1st cousins Joseph Strachan and Janet Strachan
Gen 3 – 2nd cousins Henry Strachan and Mary Lindsay
Gen 4 – 3rd cousins My father and Cathy’s father
Cathy and I are therefore 4th cousins.

Thanks to Mac for the email that prompted me to do this – he and I are 5th cousins.


8 responses to “Which nth cousin are you, and are you removed?

  1. I usually use the ancestry button but I must give this a try! Thanks Judy!

  2. Not quite – it’s number of generations less 1. This is because if there is just one generation to the shared ancestor you are not cousins, you are siblings. You are first cousins if you share grandparents, ie 2 generations away. So count the generations and subtract one, going up the shortest chain. The difference between the counts on the 2 chains is as you say, the number of ‘removes’.

  3. Not quite back again, I’m afraid! It’s number of generations less 1 if you count either the common ancestors or yourself as one of the generations. If you don’t count either of them, which I have said NOT to do, then you don’t have to subtract the 1. As the chart shows, grandchildren (i.e. children of siblings) are 1st cousins, and it does on down from there.

  4. Yep – we are in agreement! I posted the above comment after seeing the mistake on the other blog entry where you’d put 5th instead of 4th and thought you had the calculation wrong. I count the steps from person x to person y and subtract 1; you are counting the people between x and y, omitting x and y themselves. Either way works.

  5. This reminds me of the day I tried to explain “new math” to my dad! Thanks to you both for sorting this out.
    4th cousin Cathy

  6. Yes, anything with numbers in quickly gets confusing!

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