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
- 26 Your mother's father's mother's father
- 53 Your mother's father's mother's father's mother
- 107 Your mother's father's mother's father's mother's mother
- 214 Your mother's father's mother's father's mother's mother's father
- 429 Your mother's father's mother's father's mother's mother's father's mother
- 859 Your mother's father's mother's father's mother's mother's father's mother's mother
- 1718 Your mother's father's mother's father's mother's mother's father's mother's mother's father
- 3436 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father
- 6873 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother
- 13747 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother
- 27495 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother
- 54991 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother
- 109982 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father
- 219964 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father
- 439929 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother
- 879858 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father
- 1759716 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father
- 3519432 Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's father
Your mother's father's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's father, a 19x great-grandfather, is number 3519432.