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
- 14 Your mother's mother's father
- 28 Your mother's mother's father's father
- 57 Your mother's mother's father's father's mother
- 115 Your mother's mother's father's father's mother's mother
- 231 Your mother's mother's father's father's mother's mother's mother
- 463 Your mother's mother's father's father's mother's mother's mother's mother
- 927 Your mother's mother's father's father's mother's mother's mother's mother's mother
- 1855 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother
- 3710 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father
- 7420 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father
- 14840 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father
- 29680 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father
- 59361 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father's mother
- 118723 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father's mother's mother
- 237446 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father's mother's mother's father
- 474892 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father's mother's mother's father's father
- 949784 Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father's mother's mother's father's father's father
Your mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's father's father's father's mother's mother's father's father's father, a 17x great-grandfather, is number 949784.