Organising your family history files

Even if you use a computer to organise your family tree, you are still likely to end up with a lot of physical documents that you need to keep in order. There are a number of ways of doing this, the most obvious being alphabetically, but this can become confusing as your research grows, especially if you have multiple people with the same name. Another way is to use numbers from a pedigree chart of your direct ancestors.

Ahnentafel numbers (“Ancestor table” in German) are a means of listing ancestors in generation order.

Starting with yourself as number 1, your father will be number 2, and your mother number 3. Your father’s parents will be numbers 4 and 5, and your mother’s parents will be numbers 6 and 7. Your great-grandparents are then numbers 8-15. The chart below explains it.

ahnentafel chart
Four-generation pedigree chart with ahnentafel numbers. Click to enlarge.

Apart from no. 1, who can be male or female. all of the even numbers are male (blue boxes on the above diagram), and all of the odd numbers are female (pink boxes).

You can see from the chart that a father is double the child’s number, and the mother is double the child’s number, plus one. This means that you can work out the numbers of the earlier generations. For example, the father of number 15 will be number 30, and the mother of number 15 will be number 31. The parents of number 30 will be numbers 60 and 61.

We have created a editable pedigree chart that you can either print off and complete by hand, or type into the boxes. It includes the ahnentafel numbers 1-15, and can be edited to accommodate earlier generations.

This numbering system then gives an efficient way of organising all of your files – just take the number of the relevant person from the tree, and number your documents etc. with the same number.

Great-grandfather (no. 8) entry on pedigree chart

In the example above, great-grandfather is number 8 on the pedigree chart, so all the relevant documents about him are grouped together into a wallet, and filed at number 8 in a ring binder. Any artefacts or items that are too bulky to fit in a wallet or binder, can go into a box and labelled as number 8.

Wallet from ring binder, containing family group sheet, census entries etc. relating to great-grandfather, number 8 from pedigree chart

The ahnentafel numbers only cover direct ancestors, and it’s probable that you will also have documents relating to relatives who aren’t your direct ancestors. You could use an amended system for these – e.g. 8.1 for the eldest child of your great-grandfather (number 8 on your chart).

For guidance on how to fill in your pedigree chart, see our post on starting off your family history research.

If you have any queries, please email

Heritage & Local Studies Librarian

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