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
- 182 Your father's mother's mother's father's mother's mother's father
- 364 Your father's mother's mother's father's mother's mother's father's father
- 729 Your father's mother's mother's father's mother's mother's father's father's mother
- 1459 Your father's mother's mother's father's mother's mother's father's father's mother's mother
- 2918 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father
- 5836 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father
- 11673 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother
- 23347 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother
- 46694 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father
- 93389 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother
- 186779 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother
- 373559 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother
- 747118 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father
- 1494236 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's father
- 2988473 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's father's mother
- 5976946 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's father's mother's father
- 11953892 Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's father's mother's father's father
Your father's mother's mother's father's mother's mother's father's father's mother's mother's father's father's mother's mother's father's mother's mother's mother's father's father's mother's father's father, a 21x great-grandfather, is number 11953892.