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
- 366 Your father's mother's mother's father's mother's mother's mother's father
- 732 Your father's mother's mother's father's mother's mother's mother's father's father
- 1465 Your father's mother's mother's father's mother's mother's mother's father's father's mother
- 2931 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother
- 5863 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother
- 11726 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father
- 23453 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother
- 46907 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother
- 93814 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father
- 187628 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father
- 375256 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's father
- 750512 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's father's father
- 1501025 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's father's father's mother
- 3002050 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's father's father's mother's father
- 6004100 Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's father's father's mother's father's father
Your father's mother's mother's father's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's father's father's mother's father's father, a 20x great-grandfather, is number 6004100.