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
- 4 Your father's father
- 9 Your father's father's mother
- 19 Your father's father's mother's mother
- 39 Your father's father's mother's mother's mother
- 79 Your father's father's mother's mother's mother's mother
- 158 Your father's father's mother's mother's mother's mother's father
- 317 Your father's father's mother's mother's mother's mother's father's mother
- 635 Your father's father's mother's mother's mother's mother's father's mother's mother
- 1271 Your father's father's mother's mother's mother's mother's father's mother's mother's mother
- 2542 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father
- 5085 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother
- 10171 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother
- 20342 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father
- 40684 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father
- 81369 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother
- 162738 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother's father
- 325477 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother
- 650955 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother
- 1301911 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's mother
- 2603822 Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's mother's father
Your father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's mother's father, a 19x great-grandfather, is number 2603822.