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
- 38 Your father's father's mother's mother's father
- 76 Your father's father's mother's mother's father's father
- 152 Your father's father's mother's mother's father's father's father
- 304 Your father's father's mother's mother's father's father's father's father
- 609 Your father's father's mother's mother's father's father's father's father's mother
- 1219 Your father's father's mother's mother's father's father's father's father's mother's mother
- 2438 Your father's father's mother's mother's father's father's father's father's mother's mother's father
- 4877 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother
- 9755 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother
- 19511 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother
- 39023 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother
- 78047 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother
- 156094 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father
- 312189 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother
- 624379 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother
- 1248758 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's father
- 2497516 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's father's father
- 4995033 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother
- 9990067 Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother
Your father's father's mother's mother's father's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother, a 21x great-grandmother, is number 9990067.