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
- 63 Your mother's mother's mother's mother's mother
- 127 Your mother's mother's mother's mother's mother's mother
- 254 Your mother's mother's mother's mother's mother's mother's father
- 509 Your mother's mother's mother's mother's mother's mother's father's mother
- 1019 Your mother's mother's mother's mother's mother's mother's father's mother's mother
- 2038 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father
- 4077 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother
- 8154 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father
- 16309 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother
- 32619 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother
- 65239 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother
- 130478 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father
- 260957 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother
- 521915 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother's mother
- 1043830 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother's mother's father
- 2087660 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother's mother's father's father
- 4175320 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother's mother's father's father's father
- 8350640 Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother's mother's father's father's father's father
Your mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's mother's mother's mother's father's mother's mother's father's father's father's father, a 20x great-grandfather, is number 8350640.