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
- 4023 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother
- 8047 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother
- 16095 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother
- 32191 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother
- 64382 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father
- 128764 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father
- 257528 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father
- 515057 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's mother
- 1030115 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother
- 2060231 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother's mother
- 4120463 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother
- 8240926 Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father
Your mother's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father, a 20x great-grandfather, is number 8240926.