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
- 14 Your mother's mother's father
- 28 Your mother's mother's father's father
- 57 Your mother's mother's father's father's mother
- 115 Your mother's mother's father's father's mother's mother
- 230 Your mother's mother's father's father's mother's mother's father
- 460 Your mother's mother's father's father's mother's mother's father's father
- 921 Your mother's mother's father's father's mother's mother's father's father's mother
- 1842 Your mother's mother's father's father's mother's mother's father's father's mother's father
- 3685 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother
- 7371 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother
- 14742 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father
- 29484 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father
- 58969 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother
- 117939 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother
- 235879 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother
- 471758 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother's father
- 943517 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother's father's mother
- 1887035 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother
- 3774070 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's father
- 7548140 Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father
Your mother's mother's father's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father, a 20x great-grandfather, is number 7548140.