Ahnentafel Ancestor Numbering System

There are many ways to organize ancestors in reports. In this blog from December 2016, we cover two numbering systems; Register and SOSA.  Now, let’s review the Ahnentafel Ancestor Table, German for ancestor table.

The Ahnentafel Ancestor Table is a German genealogical numbering system that lists a person’s direct ancestors in a fixed sequence of ascent. This system is actually quite similar to the SOSA Numbering System.

1 –  Main Person

2 – the main person’s father

3 – the main person’s mother

4 and 5 – Paternal grandparents

6 and 7 – Maternal grandparents

Even number people are male. (0,2,4,6,8,10,12,14,16,18…..)

Odd number people are female. (1,3,5,7,9,11,13,15,17,19…..)

The number of any person’s father is double the person’s number, and a person’s mother is double the person’s number plus one.

Example: If you are using or reading or discussing a report, and you see mention of ancestor #35, you can quickly determine a few things.

  1. That person is a female.
  2. This female is a third great grandmother on the paternal side to person #1.

For a great visual on the Ahnentafel Ancestor Table, check out this diagram from LostCousins.

Binary Ahnentafel

Traditionally binary is used as a series of 1’s and 0’s. Binary is the basis of all computer language. So how does binary work into a genealogy numbering system?

Atree, also known as the Binary Ahnentafel method uses the same numbering as Ahnentafel method described above but uses binary numbers instead (1’s and 0’s), or in this case M and F. M for male, F for female.

This Atree Binary Method can be easier to understand the ancestry path from the main person going back the numerous generations.

Example: If you are using or reading or discussing an Atree Binary Method report, and you see mention of ancestor MFMMMMM, you can quickly determine a few things.

  1. The main person is male
  2. That specific person in question is also male.
  3. This male is a fifth great-grandfather on the maternal side to person M.

Have you ever seen the Ahnentafel Genealogical Numbering System or the Atree Binary Method? Is this something you may have used when creating a report of your ancestors?