What is Ahnentafel?

The world of genealogy is littered with numerous strange terms and phrases and one of the most unusual is Ahnentafel. It’s the kind of word that makes you think it’s an angelic character from the TV show Supernatural or a topical cream for some unfortunate rash!

Luckily, it is neither of those things. It is, however, a very important concept in written genealogy.

In this post we will look at what Ahnentafel is and how it is used to help us better understand family history.

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What Is Ahnentafel?

The German word Ahnentafel essentially translates as ancestral table but this does not mean it is the German word for family tree. This term is actually more complex than the family trees we can look at and easily understand.

Ahnentafel is a genealogical numbering system that lists a person's direct ancestors using a fixed sequence. The subject who in your own tree would be yourself is given the number one. Subsequently numbers are assigned to your ancestors with the male line being first so dad is number two and mom is number three. This continues on through your tree but we will go into this in more detail later in the post.

So rather than being a family tree chart, Ahnentafel is actually a system that allows us to write up a lineage for a person in a more compact way. This is beneficial for sending family history information in an email or for writing a lineage book.

What Are the Origins of Ahnentafel?

As you might imagine the concept of Ahnentafel derives from the group of people for whom lineage is considered so vitally important. It was around the 1590s when Austrian diplomat and historian Michael Eytzinger first published the principles of this system. It was already an established practice among the royal houses of Europe.

Ahnentafel is actually also sometimes referred to as the Eytzinger Method. Other variations of the method exist including the Sosa Method created by Jeronimo de Sosa and the Sosa-Stradonitz Method created by Stephan Kekule von Stradonitz who developed his own spin based on the Sosa Method.

How Are Ahnentafel Charts Useful?

You likely already have a family tree created so why would you have any use for this numbering system? This is a good question and in truth you personally may not have a use for it but there are many uses that Ahnentafel can be put to.

  • Standard pedigree charts take up a lot of space
  • It might not be practical to display your family information in a pedigree chart
  • The Ahnentafel numbers are a uniform way to refer to your ancestors
  • It is a fast and efficient way to create a list of your ancestors
  • It allows you to easily determine how people are related to you
  • Ahnentafel takes up far less space than a pedigree chart does
  • It is far easier to share an Ahnentafel document than a family tree pedigree chart

It may not look as visually appealing as a pedigree chart which may have family pictures attached to it but a written Ahnentafel document can be very useful. Imagine creating a document to share with your family regarding the family tree and perhaps hyperlinking the names to take them to a profile on the individuals.

This system is superior in terms of being able to easily share it and this is why it is often seen in family lineage books. I have a couple of these types of books that pertain to my wife’s family which trace the lineage of some of her earliest ancestors in America.

How Is an Ahnentafel Chart Made?

In order to make an Ahnentafel chart you must first start from whatever you have in terms of a family tree. This may be just a few generations or it could be several. It just depends on how far you have managed to get so far.

Using a piece of paper or perhaps a digital format such as Word or Google Docs you can start plotting out your Ahnentafel chart. First, you need to decide on what information to include in this chart. Often dates of birth and death are essential. Including places of birth may also be helpful or other minor biographical information.

Be aware that some of the family tree software you already use might actually allow you to create an Ahnentafel chart from your established tree. If it does then you don’t even need to write up your own version.

There may be missing individuals in your tree who you have not yet identified. The position of this individual in your tree should still be assigned the appropriate number so you simply skip to the next number and person in the tree.

In doing this if you later discover the identity of this ancestor you can easily insert that person into the Ahnentafel chart without switching numbers. It is therefore important that the number refers to the relationship order rather than the person.

How Does the Numbering System Work?

As mentioned the Ahnentafel system is somewhat patronymic in that it favors the male ancestors first. I know this may not sit well with some and I fully understand that. In my personal opinion for your own Ahnentafel you can prioritize the female ancestors as long as you keep the pattern going in the right way.

Obviously if you were doing this as part of a submission for an official genealogical accreditation it is best to do so in the standard method that is understood and universally used. It is this method I will use to give you the example of how the numbering system works.

The numbering system is probably the most confusing part but once you master the concept it is actually pretty easy to understand it and use it. Below is how the numbering system works for over 4 generations of your family from you to your great grandparents.

  • You = 1
  • Your father = 2
  • Your mother = 3
  • Your father’s father = 4
  • Your father’s mother = 5
  • Your mothers’ father = 6
  • Your mother’s mother = 7
  • Your father’s father’s father = 8
  • Your father’s father’s mother = 9
  • Your father’s mother’s father = 10
  • Your father’s mother’s mother = 11
  • Your mother’s father’s father = 12
  • Your mother’s father’s mother =13
  • Your mother’s mother’s father = 14
  • Your mother’s mother’s mother = 15

This sequence continues on as far as you wish to take it depending on how far you can get in your tree. As mentioned before if for example you do not know the identity of your father’s mother’s mother you would still allocate the number eleven to this relationship.

Not knowing the identity now does not mean you will never figure this information out and if you do later and you assigned number 11 to the next in line your mother’s father’s father then you have no place to put this information. You would have to change the numbers on all of the individuals later in the tree to make it work.

If you are looking for further clarification of how this works try this simple task. Open up your family tree and view it as a pedigree chart from left to right. Your name should be on the left. Now count yourself as number one and then move to the next generation. Your dad will be likely above your mother so start at the top and count down.

Move through the generations counting each individual moving left to right and returning to the top after each generation. If you do this you will note by the time you get to your great grandparents there are 15 people in your direct line including yourself. If you then count your great-great grandparents you will reach 31 individuals.

What if Individuals Appear in Your Tree Twice?

You may have heard of endogamy or pedigree collapse which is a thing that without fail will occur at some point in all our family trees. I won’t go into the details of this right now but it is important in the numbering system.

In my own family tree my great grandparents Thomas Edward Davies and Bertha Jones were first cousins once removed. This means that Thomas’s paternal grandparents William Davies and Elizabeth Humpheys appear in my Ahnentafel at 32 and 33 respectively.

Also as the maternal great grandparents of Bertha Jones, William Davies and Elizabeth Humphreys again appear at 78 and 79 in my Ahnentafel chart. So even though they are the same individuals they are in these different positions in my direct lines.

William Davies then is 32 and 78 in my chart and his wife Elizabeth Humphreys is 33 and 78 in the numbering system. Both numbers apply so again we can’t skip them or the system gets thrown off the rails.

Calculating a Person's Ahnentafel Number

It is possible to calculate a person's number in an Ahnentafel chart without actually writing it all down; you simply have to use a little basic math. The important factor to remember for this is that a father’s number will be twice that of his child. Also a mothers number will be twice her child’s plus 1.

In the below example we will use some names from my own tree to calculate the Ahnentafel number of my 4 x great grandfather John Minton.

  • Me 1 x 2 (father) = 2
  • Father 2 x 2 + 1 (his mother) = 5
  • Paternal grandmother 5 x 2 + 1 (her mother) = 11
  • Paternal great grandmother 11 x 2 + 1 (her mother) = 23
  • Paternal great-great grandmother 23 x 2 (her father) = 46
  • Paternal great-great-great grandfather 46 x 2 (his father/ John Minton) = 92

I also sat and counted using my tree so I can confirm that this works out doing it both ways but obviously using just six basic sums you can determine what number your ancestor should fall in the tree. Simply remember the two rules: the father is twice the number assigned to their child and the mother is twice plus one.

Is There a Limit to the Ahnentafel Chart?

In theory there is no limit to how long an Ahnentafel chart can be; it really only depends on how many ancestors you have identified. The numbering system can go on indefinitely but of course if you hit a point where you no longer have the identities to match the numbers there is no point continuing.

We may know what number to assign to all of our 20 x great grandparents but if we do not know their identities there really is no point in listing them. There are limits to how far back we can reasonably trace our family tree.


The Ahnentafel system is a very organized way in which you can number your ancestors in a list format to better understand how they are related to you. It is a far more compact system than a standard pedigree chart and works great for written family histories.

A few simple mathematical rules can allow you to quickly calculate what number to attribute to a certain ancestor. So give the numbering system a try, practice it a little and you might be surprised at how quickly it starts to make sense to you.

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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