3 Things to Do with Ahnentafel Numbers

This numbering system takes all the guesswork out of which ancestor is which.

Did you realize each of your direct ancestors has a number? It's a number that never changes. And my ancestor #126 is the same as your ancestor #126. They're not the same person, but they are our mother's mother's mother's mother's mother's father.

We call this numbering system Ahnentafel numbers. Ahnentafel is German for ancestor (ahnen) table (tafel). Here's how it works.

In your family tree, you are #1, your father is #2, and your mother is #3. The rest follows a pattern. All male ancestors have even numbers and all female ancestors have odd numbers.

Ahnentafel numbers let me sort a column of ancestors easily.

You can figure out the numbers yourself. Let's use your father, Ahnentafel #2, as an example. His father is double his number (so, 4) and his mother is 1 more than his father (so, 5).

One of my 2nd great grandmothers is #31, so her father is double that (62) and her mother is 1 more than her father (63).

Family Tree Maker has an Ahnentafel report to figure them all out for you. Choose yourself, or anyone in your tree who you want to be #1, and run the report. But what can you do with these numbers?

Here are 3 useful things you can do with your Ahnentafel numbers.

1. Add Them to Your Grandparent Chart

I created a grandparent chart to keep track of all the direct ancestors I've identified. Here's a blank chart you can use—now updated with numbers in the cells. Some of the longer columns were getting pretty full. That's when I realized Ahnentafel numbers would help me keep the people in each column in the right order. It helps me see where the missing ancestors belong, too.

Be sure to see 3 Ways to Find Double Ancestors in Your Family Tree which highlights another benefit of using Ahnentafel numbers in your grandparent chart.

2. List Them Out

Let's say you want to see who's missing, but you don't want a grandparent chart. You can list your ancestors in numerical order, like this:

1. you
2. father
3. mother
4. paternal grandfather (your father's father)
5. paternal grandmother (your father's mother)
6. maternal grandfather (your mother's father)
7. maternal grandmother (your mother's mother)
8. great-grandfather (your father's father's father)
9. great-grandmother (your father's father's mother)
10. great-grandfather (your father's mother's father)
11. great-grandmother (your father's mother's mother)
12. great-grandfather (your mother's father's father)
13. great-grandmother (your mother's father's mother)
14. great-grandfather (your mother's mother's father)
15. great-grandmother (your mother's mother's mother)

Continue the list as far as you can until you hit a missing number. That's the closest ancestor you're missing.

Here's a simple tool to help you figure out which number belongs to which ancestor. Simply enter a number in the box to see their relationship to you, like #120, your mother's mother's mother's father's father's father.

The first ancestor I'm missing is Ahnentafel #59, my mother's mother's father's mother's mother, or my 3rd great grandmother.

I'm not missing another one until #109, my mother's father's mother's mother's father's mother, or my 4th great grandmother.

My missing 3rd great grandmother and handful of missing 4th great grandparents need my attention. If I didn't look at my tree in this way, I wouldn't know exactly who is missing.

This section of my ancestor chart shows each ancestor's Ahnentafel number.

3. Create a Custom Ahnentafel Chart

I added a new custom Ahnentafel field in Family Tree Maker. (Go to Edit / Manage Facts / New. Use Ahnentafel for the Fact label, but uncheck the boxes for Date and Place.) I can add the proper Ahnentafel number to each of my direct ancestors.

Now I can create my vertical pedigree chart and see the numbers. It's easier to see exactly who's missing in this graphical format.

No matter how you do it, think of your Ahnentafel numbers as a tool to show you where to focus your research work. I really want to find the name of my #59.

You may not think of genealogy as a numbers game, but these numbers can help you fortify your family tree. Don't miss the companion article on this topic. Plus, I found a 4th great thing to do! Make your own Elder Scroll.

And speaking of grandparents:

• How to Visualize Your Ancestor-Finding Progress
• Step-by-Step Discovery of My 5th Great Grandparents
• Case Study on 'Where Did Grandpa Come From?'