Ancestor Numbers
An Ancestor Number (the proper name is an Ahnentafel number) says exactly where a direct ancestor sits in your family tree. You are always number 1. Anyone's father has double their number, and their mother double plus one: so your father is 2 and your mother 3, your father's parents are 4 and 5, your mother's parents 6 and 7, and so on. That's why every man in your tree (apart from you) has an even number and every woman an odd one.
Entering the Ancestor Numbers of your direct ancestors on My Ancestors keeps your records accurate, helps your cousins work out how they're related to you, and tells apart two lines that happen to share a surname.
Print our Ancestor Chart Every box on the chart shows its number, five generations back from you.
Peter Calver, who founded LostCousins, explained Ancestor Numbers in his newsletter of 25 December 2023 (Why are your female ancestors odd?).
Find a number by stepping back from you
Choose father or mother, one generation at a time, until you reach the person you want.
- 1 You
- 3 Your mother
- 6 Your mother's father
- 12 Your mother's father's father
- 24 Your mother's father's father's father
- 49 Your mother's father's father's father's mother
- 99 Your mother's father's father's father's mother's mother
- 198 Your mother's father's father's father's mother's mother's father
- 397 Your mother's father's father's father's mother's mother's father's mother
- 795 Your mother's father's father's father's mother's mother's father's mother's mother
- 1590 Your mother's father's father's father's mother's mother's father's mother's mother's father
- 3180 Your mother's father's father's father's mother's mother's father's mother's mother's father's father
- 6361 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother
- 12723 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother
- 25446 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father
- 50893 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother
- 101787 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother's mother
- 203575 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother's mother's mother
- 407150 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father
- 814301 Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's mother
Your mother's father's father's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's mother, a 17x great-grandmother, is number 814301.