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
- 12 Your mother's father's father
- 25 Your mother's father's father's mother
- 51 Your mother's father's father's mother's mother
- 102 Your mother's father's father's mother's mother's father
- 204 Your mother's father's father's mother's mother's father's father
- 409 Your mother's father's father's mother's mother's father's father's mother
- 819 Your mother's father's father's mother's mother's father's father's mother's mother
- 1639 Your mother's father's father's mother's mother's father's father's mother's mother's mother
- 3278 Your mother's father's father's mother's mother's father's father's mother's mother's mother's father
- 6557 Your mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother
- 13115 Your mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother
- 26230 Your mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's father
- 52461 Your mother's father'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 mother
- 104922 Your mother's father'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 mother's father
- 209844 Your mother's father'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 mother's father's father
- 419689 Your mother's father'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 mother's father's father's mother
- 839379 Your mother's father'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 mother's father's father's mother's mother
- 1678758 Your mother's father'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 mother's father's father's mother's mother's father
Your mother's father'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 mother's father's father's mother's mother's father, a 18x great-grandfather, is number 1678758.