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
- 15 Your mother's mother's mother
- 31 Your mother's mother's mother's mother
- 62 Your mother's mother's mother's mother's father
- 125 Your mother's mother's mother's mother's father's mother
- 251 Your mother's mother's mother's mother's father's mother's mother
- 502 Your mother's mother's mother's mother's father's mother's mother's father
- 1005 Your mother's mother's mother's mother's father's mother's mother's father's mother
- 2011 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother
- 4022 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father
- 8044 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father
- 16089 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother
- 32178 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father
- 64356 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father
- 128713 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother
- 257427 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother
- 514854 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father
- 1029708 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father's father
- 2059416 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father's father's father
- 4118833 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father's father's father's mother
- 8237666 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father's father's father's mother's father
- 16475333 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father's father's father's mother's father's mother
Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's father's mother's mother's father's father's father's mother's father's mother, a 21x great-grandmother, is number 16475333.