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
- 2 Your father
- 5 Your father's mother
- 11 Your father's mother's mother
- 23 Your father's mother's mother's mother
- 47 Your father's mother's mother's mother's mother
- 95 Your father's mother's mother's mother's mother's mother
- 190 Your father's mother's mother's mother's mother's mother's father
- 381 Your father's mother's mother's mother's mother's mother's father's mother
- 763 Your father's mother's mother's mother's mother's mother's father's mother's mother
- 1526 Your father's mother's mother's mother's mother's mother's father's mother's mother's father
- 3053 Your father's mother's mother's mother's mother's mother's father's mother's mother's father's mother
- 6106 Your father's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father
- 12212 Your father's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father
- 24425 Your father's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father's mother
- 48851 Your father's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father's mother's mother
- 97702 Your father's mother's mother'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
- 195404 Your father's mother's mother'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's father
- 390809 Your father's mother's mother'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's father's mother
- 781618 Your father's mother's mother'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's father's mother's father
- 1563237 Your father's mother's mother'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's father's mother's father's mother
- 3126475 Your father's mother's mother'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's father's mother's father's mother's mother
- 6252950 Your father's mother's mother'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's father's mother's father's mother's mother's father
- 12505900 Your father's mother's mother'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's father's mother's father's mother's mother's father's father
Your father's mother's mother'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's father's mother's father's mother's mother's father's father, a 21x great-grandfather, is number 12505900.