08/05/2017
Share this story Share on Facebook icon Share on Twitter icon Share on Pinterest icon Share on Google Plus icon Share on Linked In icon Share via Email icon

Relationship calculator - how to work out family relationships

1cca8779-bc78-42a6-8f97-e254b90f7482

What is a second cousin? Or a third cousin once removed? Work out who’s who on your family tree with our guide to relationship calculator terms.

Although most of us are confident in working out the cousins, aunts, uncles and even great-grandparents on our family tree, terms such as ‘second cousin once removed’ or ‘natural child’ can be more of a challenge. So here’s how to calculate who’s who when exploring family relationships.

Cousin relationships

We’ll begin with cousins, who are of course, the children of an individual’s uncle or aunt. The words ‘first’, ‘second’ or ‘third’ and so on, simply describe the number of generations between the people concerned and their common ancestor.

So –

  • first cousins share the same grandparents
  • second cousins have great-grandparents in common
  • third cousins share the same great-great-grandparents.

The words ‘once removed’ when describing family members means that the first, second, etc cousins are in a different generation to each other. So, for example, a second cousin once-removed is the child or parent of a second cousin.

Base and natural child

During your family tree research, you will probably come across one or more terms used to describe an illegitimate child. Such terms can include -

  • Base born
  • Natural
  • Bastard

Each of the above can mean a child born out of wedlock, ie an illegitimate child. Although such terms can vary from document to document, as a rule of thumb, a ‘base’ child is usually the child of a single mother, whereas ‘bastard’ generally means the child of an unmarried but established couple’ and ‘natural child’ refers to a blood child rather than one who is adopted, or a step-child.

Family Tree magazine’s easy to use relationship calculator

For a quick and easy way to discover who’s who on your family tree, check out Family Tree’s handy relationship calculator. To use the calculator, simply visualise how the ancestor that you and another relative have in common would describe you, eg you might both be a great-grandchild of that ancestor. So on the horizontal column, find ‘great grandchild’ and with your finger, move along the chart, until the vertical column for ‘great grandchild’ meets that point – and you’ll see that the two of you are second cousins.

Or if you are that ancestor’s grandchild and your relative would be their great-grandchild, find the column on the horizontal row, then follow along looking at where the vertical column ‘great grandchild’ meets that point – the two of you are first cousins once removed, ie you are first cousins in different generations.

Find Family Tree’s handy relationship calculator here.

How much DNA do you share with your ancestors?

Don't miss the digital guide How To Start Your Family Tree – available to download now.

How To Start Your Family Tree is an interactive beginners guide giving you everything you need to get started with tracing your family history and discovering your ancestors. This collected edition of beginner features, previously published in Family Tree, is packed full of expert tips, how-to advice and lots of ideas for starting your family tree from scratch and writing up your family history.

image copyright Library of Virginia, Rice Collection, reproduction no digitool1.lva.lib.va.us:8881/R

Back to "Relationship calculator" Category

08/05/2017 Share this story   Share on Facebook icon Share on Twitter icon Share on Pinterest icon Share on Google Plus icon Share on Linked In icon Share via Email icon

Recent Updates

Theory of Family Relativity™update announced by MyHeritage

MyHeritage have today (18 Jul 2019) announced an update to their Theory of Family Relativity™tool, offering ...


75,000 new names added to War Memorial records at TheGenealogist

TheGenealogist has released over 658 War Memorials with 75,973 new individuals, meaning there are now a total ...


How to order a birth certificate & why you need to

Starting out on your family history journey, and wondering why you need to buy birth certificates for your ...


5 essential things you need to start your family tree

Start your family tree today with our expert advice on things you'll need to get going ...


Other Articles

Top tips on organising your family history research

Get your family history research under control with these tips for organising both paper-based and digital ...



New Norfolk family history records reveal the parents of illegitimate children

TheGenealogist has released over half a million new parish records for Norfolk into their Parish Records ...


Brush up on the Yorkists & Lancastrians

While we love our own family histories, they mean so much more with a bit of historical background. Here ...