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
- 22 Your father's mother's mother's father
- 45 Your father's mother's mother's father's mother
- 91 Your father's mother's mother's father's mother's mother
- 183 Your father's mother's mother's father's mother's mother's mother
- 367 Your father's mother's mother's father's mother's mother's mother's mother
- 734 Your father's mother's mother's father's mother's mother's mother's mother's father
- 1469 Your father's mother's mother's father's mother's mother's mother's mother's father's mother
- 2939 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother
- 5879 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother
- 11759 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother
- 23518 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father
- 47036 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father
- 94073 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother
- 188146 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father
- 376293 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother
- 752587 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother's mother
- 1505175 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother's mother's mother
- 3010350 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother's mother's mother's father
- 6020701 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother's mother's mother's father's mother
- 12041402 Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother's mother's mother's father's mother's father
Your father's mother's mother's father's mother's mother's mother's mother's father's mother's mother's mother's mother's father's father's mother's father's mother's mother's mother's father's mother's father, a 21x great-grandfather, is number 12041402.