Ahnentafel Numbers

Now what might you ask is an Ahnentafel Number? If you are interested in family history then this is for you.

An Ahnentafel is a list of one's ancestors with each one numbered in a sequential manner that makes it easy to calculate relationships. The Ahnentafel method is the most common method of numbering ancestors. Ahnentafel is a German word that translates as “ancestor table” or, literally, a list of one’s ancestors.

In an Ahnentafel numbering system, the base person is assigned the number one. The father of each person is assigned a number equal to double the child’s number. The mother of each person is assigned a number equal to double the child’s number plus one. As a result, the number of any child is one-half that of their parent, ignoring any remainder. For the first four generations, the numbers assigned a given person and their ancestors reflect the following relationships:

1. person
2. father
3. mother
4. paternal grandfather
5. paternal grandmother
6. maternal grandfather
7. maternal grandmother
8. great-grandfather
9. great-grandmother
10. great-grandfather
11. great-grandmother
12. great-grandfather
13. great-grandmother
14. great-grandfather
15. great-grandmother

Apart from No. 1, who can be either male or female, all even-numbered persons are male, and all odd-numbered persons are female.

The table below shows how the system works in a diagrammatical form.

8. great-grandfather
4. paternal grandfather-|
| 9. great-grandmother
2. Father--|
| | 10. great-grandfather
| 5. paternal grandmother-|
| 11. great-grandmother
|
1. You-|
|
| 12. great-grandfather
| 6. maternal grandfather-|
| | 13. great-grandmother
3. Mother--|
| 14. great-grandfather
7. maternal grandmother-|
15. great-grandfather

The primary disadvantage of Ahnentafel numbers is that the size of each number when going back many generations becomes quite large. Someone with a documented line of descent from Charlemagne may be using Ahnentafel numbers in the billions.

True ahnentafel lists the person's full name, along with dates and places of birth, marriage, and death, if known.