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
- 7 Your mother's mother
- 15 Your mother's mother's mother
- 31 Your mother's mother's mother's mother
- 63 Your mother's mother's mother's mother's mother
- 127 Your mother's mother's mother's mother's mother's mother
- 254 Your mother's mother's mother's mother's mother's mother's father
- 509 Your mother's mother's mother's mother's mother's mother's father's mother
- 1019 Your mother's mother's mother's mother's mother's mother's father's mother's mother
- 2039 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother
- 4079 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother
- 8158 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father
- 16317 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother
- 32635 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother
- 65271 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother
- 130542 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father
- 261084 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father
- 522168 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father
- 1044336 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father
- 2088672 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's father
- 4177344 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's father's father
- 8354688 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's father's father's father
- 16709376 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's father's father's father's father
Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's father's father's father's father, a 21x great-grandfather, is number 16709376.