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
- 2 Your father
- 5 Your father's mother
- 11 Your father's mother's mother
- 23 Your father's mother's mother's mother
- 47 Your father's mother's mother's mother's mother
- 95 Your father's mother's mother's mother's mother's mother
- 191 Your father's mother's mother's mother's mother's mother's mother
- 382 Your father's mother's mother's mother's mother's mother's mother's father
- 765 Your father's mother's mother's mother's mother's mother's mother's father's mother
- 1531 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother
- 3062 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father
- 6124 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father
- 12249 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother
- 24499 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother
- 48998 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father
- 97996 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father
- 195992 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father
- 391984 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father
- 783968 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father's father
- 1567936 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father's father's father
- 3135872 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father's father's father's father
- 6271744 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father's father's father's father's father
- 12543489 Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father's father's father's father's father's mother
Your father's mother's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's father's father's father's father's father's father's father's father's mother, a 21x great-grandmother, is number 12543489.