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 (opens in a new tab) 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
- 30 Your mother's mother's mother's father
- 61 Your mother's mother's mother's father's mother
- 123 Your mother's mother's mother's father's mother's mother
- 247 Your mother's mother's mother's father's mother's mother's mother
- 495 Your mother's mother's mother's father's mother's mother's mother's mother
- 991 Your mother's mother's mother's father's mother's mother's mother's mother's mother
- 1982 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father
- 3965 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father's mother
- 7931 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother
- 15863 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's mother
- 31727 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's mother's mother
- 63454 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father
- 126909 Your mother's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's mother's mother's father's mother
- 253819 Your mother's mother's mother's father'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
- 507639 Your mother's mother's mother's father'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
- 1015279 Your mother's mother's mother's father'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 mother
- 2030559 Your mother's mother's mother's father'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 mother's mother
- 4061119 Your mother's mother's mother's father'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 mother's mother's mother
- 8122239 Your mother's mother's mother's father'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 mother's mother's mother's mother
- 16244479 Your mother's mother's mother's father'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 mother's mother's mother's mother's mother
- 32488958 Your mother's mother's mother's father'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 mother's mother's mother's mother's mother's father
- 64977917 Your mother's mother's mother's father'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 mother's mother's mother's mother's mother's father's mother
- 129955835 Your mother's mother's mother's father'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 mother's mother's mother's mother's mother's father's mother's mother
- 259911671 Your mother's mother's mother's father'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 mother's mother's mother's mother's mother's father's mother's mother's mother
- 519823342 Your mother's mother's mother's father'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 mother's mother's mother's mother's mother's father's mother's mother's mother's father
Your mother's mother's mother's father'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 mother's mother's mother's mother's mother's father's mother's mother's mother's father, a 26x great-grandfather, is number 519823342.