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
- 13 Your mother's father's mother
- 27 Your mother's father's mother's mother
- 55 Your mother's father's mother's mother's mother
- 110 Your mother's father's mother's mother's mother's father
- 221 Your mother's father's mother's mother's mother's father's mother
- 443 Your mother's father's mother's mother's mother's father's mother's mother
- 886 Your mother's father's mother's mother's mother's father's mother's mother's father
- 1773 Your mother's father's mother's mother's mother's father's mother's mother's father's mother
- 3547 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother
- 7094 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father
- 14188 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father
- 28377 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother
- 56755 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother
- 113510 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's father
- 227021 Your mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's father's mother
- 454043 Your mother's father's mother's mother's mother'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
- 908087 Your mother's father's mother's mother's mother'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
- 1816174 Your mother's father's mother's mother's mother'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
Your mother's father's mother's mother's mother'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, a 18x great-grandfather, is number 1816174.