How Does a Family Tree Work?

If you are just starting out on your journey of family history research you may not fully understand as of yet how it all works. Allow me to assure you there is never any harm in asking a question because we don’t know what something is until we learn about it.

The core element of our family research is something called our family tree which to those who don’t know may seem like a nebulous term. In this post we will talk about what a family tree is, how it works and how you can get started with your own voyage of family history discovery.

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What Is a Family Tree?

You likely know all the members of your immediate family, parents, aunts, uncles, siblings, nieces, nephews and grandparents. There is no confusion as to how these people are related to you and it’s something you understand from a very young age.

There is however far more to our family than these close relatives including many people who we may not even know at all. We have cousins of all different levels of distance and we have direct ancestors who may have died decades or hundreds of years before we were even born.

We could find out about these people through research and just write them all down in a list but this would actually be a very confusing way to achieve this. In order to create a more visually appealing and frankly a more understandable representation of our family the idea of a family tree was created.

The design of a physical tree works as a good analogy for what a family tree is. Roots lead to a trunk which then leads to branches and further still to small twigs. If we consider ourselves the roots and trunk of the tree then the next biggest branches represent our two parents. The branches that grow from those branches represent their parents and so on.

Essentially we start with ourselves and use lines to indicate our relationships to our family. A direct line goes from us to our parents who themselves have direct lines to their own parents. When we include non-direct line relatives like uncles and aunts we do not have a direct line to them but they do have lines that lead to your grandparents.

A family tree then is a visual representation of your family members linked together to make it more clear how you are related to someone. It will include names and biographical information such as dates of birth and death. You may even have pictures attached to your tree to show what your ancestors looked like.

In the image below you will see how an uncle is related to you and how they would appear on a family tree.

What Does a Family Tree Look Like?

Although based on the concept of an actual tree, displaying your family as a tree shape isn't actually the most efficient way to do it. You can of course make small decorative trees with limited family members on it but for a full tree there is a much better design.

A good family tree is a simple chart diagram that allows you to display your family relationships in an ordered and clear fashion. There are different types of charts that you can create, some that show only your direct line family who are those who you directly descend from and those that show your indirect family as well.

As mentioned, indirect family members are people who may not be direct ancestors of descendants of yours but they share a common ancestor with you. These trees may also include the people who have married people in your family like the spouse of your uncles and aunts. They are not blood relatives but are actually related to you by marriage.

In the diagram below you will see a chart that traces your line back three generations of your direct ancestors.

It shows you leading to your parents who then lead to your grandparents and finally your great grandparents. Each person on this chart has two parents and this continues back generation after generation.

Theoretically each generation you go back in your tree the number of ancestors you have from each generation doubles from the previous generation. The reason I say theoretically is because eventually something called pedigree collapse occurs and you may find the same ancestors in two or more places in your family tree. We won't worry about pedigree collapse in this post though as it is a more advanced concept that can seem very confusing.

Ancestral and Descendant Charts

There are two directions you can take with a family tree: you can create one that traces ancestry by starting with a living person such as yourself and then trace back in time through the generations.

Alternatively you could try and trace the descendants of someone who lived many years ago, perhaps a great-great-great grandparent of yours. In this kind of chart you start with the ancestral couple and then work forwards in time.

In the image below you will notice that we start with Benjamin Davies and Charlotte Rees and move down to their sons Thomas and Benjamin Jr. We list their respective wives and their sons Thomas Jr. and Benjamin III.

We trace from the grandparents down to the grandchildren who as the children of siblings are considered as first cousins. So in this chart Thomas Jr. and Benjamin III are first cousins to each other.

So an ancestral chart traces back through the generations to discover who our ancestors were. A descendant chart is used to trace the people who descend from individuals who lived in the past. You could even create a descendant chart for your own grandparents especially if they had more than one child.

How Do You Start a Family Tree?

The first step in building your family tree is gathering together all the information you can about your family. You will need names of parents, grandparents, uncles, aunts, siblings, cousins and any children as well.

You can also use our cousin calculator to visualize those relationships and help you to start the basis of your family tree.

Having exhausted your own knowledge it is time to reach out to the older members of your family: parents, grandparents if you are lucky enough, maybe even great grandparents. Find out from these family members what they know about their parents and grandparents.

As an example, if your great grandmother can tell you who her grandparents were, when they were born and where they came from you already have reached some of your great-great-great grandparents. The more you can learn about the family including any stories or rumors the better prepared you are to start forming your family tree and perhaps even expanding beyond your current family's knowledge.

I know my grandfather was delighted to discover that his uncle Isaac, who died during the First World War a few years before he himself was born, was a hero. He had heard stories as a child but never knew the man himself.

As you gather your information take detailed notes and if you can perhaps record your conversations with your older family members. Not only will you be able to listen back for anything you may have missed but also it can be a great memory to relive many years from now.

Having gathered your initial details it is time to start plotting out the family tree which you could do by sketching it out on a piece of paper like genealogists had to do before computers or these days you can build your tree on any number of genealogy websites.

Some of these sites are completely free while others may require a membership. The plus of using one of these sites is that the information you input may actually help lead you to records that your ancestors are mentioned in. This could in turn lead you to discovering the identity of the next generation of your family tree.

Who Should Be in Your Family Tree?

I have spent many hours on genealogy forums and Facebook groups and seen many opinions as to who to include and exclude from a family tree. There are some gray areas when it comes to family such as adoption and relationship by marriage.

Most trees may start with just your direct ancestors such as parents, grandparents etc and perhaps your siblings. This is of course fine but you may reach a point where you start to notice that you have a notable great uncle or you might be a distant cousin of some famous individual.

Kevin Bacon for example went on a famous genealogy website and discovered he had a famous cousin who also happened to be his wife Kyra Sedgewick. You don’t have to include these non-direct members of your family but just be aware they are people with whom you share common ancestors.

When you add the siblings of great grandparents and their respective children you are starting to build what is known as a “wide” family tree. There is a benefit to doing this as sometimes those collateral non direct family members might hold the key to determining the identity of your next generation of ancestors.

It is often wise to know who else was in your ancestors' circle of friends and family as this can lead to evidence that proves a theory or gives you a hint as to where to research next.

I managed in my own tree to trace directly back to around the mid 18th century with my own ancestors all the way back to my 5x great grandparents. Once I had got back I started to build out wider research of the siblings of my direct ancestors in search of new information. Today my tree of ancestry has 1,899 individuals.

Should You Exclude Adopted or Married in Family?

Some people may not know their birth parents and only have their adopted parents as any kind of family. There may be some who try to trace their birth parents while others might build their tree based on the adopted family that raised them.

The decision as to including or excluding adopted family members from a tree is a very personal one and really there is no genealogical standard for this. It is wise to record the nature of the relationship but ultimately your family is your family regardless of how that came about.

When it comes to those who marry into the family they certainly are part of the family and likely would be the parents of some of your cousins. You would likely not research their family lines as part of your own tree but they as individuals could certainly be included in your tree.

The people who enter the family by marriage are still important to the family as a whole and this might also include former spouses of your parents. They could be a parent to a half sibling which is certainly the case on both sides of my own family.


A family tree is an organized chart that contains names and biographical data regarding your family members. It is a visual representation that can help you trace how you might be related to someone and helps keep your research ordered and clear.

A tree can range in size from a small one tracing a few generations to an extensive one that lists cousins, and many generations of your ancestry. It might include people who have married into the family or even adopted children who were also considered part of the familial group.

Neil Edwards

Neil Edwards

Genealogist and family-tree research specialist

Neil was born in Shropshire, England surrounded by centuries of living history. His interest in the past has been a lifelong passion leading to undergraduate degrees in both Economic History & Geography and History & Politics.

This interest in history quickly translated to family history when he moved to the U.S. in 2010. It was here that he began working on his own family tree as well as that of his American wife. That research allowed him to gain a wealth of experience working with both U.S. and European genealogical documents and studying their best uses in researching family history.

Following 9 years of honing his genealogical research skills, Neil was proud to have earned a certificate in Genealogical Research from Boston University in late 2019. Neil also took part in the research process for a Duke University study into the families of 19th Century UK Members of Parliament.

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