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
- 8 Your father's father's father
- 16 Your father's father's father's father
- 33 Your father's father's father's father's mother
- 67 Your father's father's father's father's mother's mother
- 134 Your father's father's father's father's mother's mother's father
- 269 Your father's father's father's father's mother's mother's father's mother
- 539 Your father's father's father's father's mother's mother's father's mother's mother
- 1078 Your father's father's father's father's mother's mother's father's mother's mother's father
- 2157 Your father's father's father's father's mother's mother's father's mother's mother's father's mother
- 4314 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father
- 8628 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father
- 17257 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother
- 34514 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father
- 69029 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother
- 138059 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother
- 276119 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother's mother
- 552239 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother's mother's mother
- 1104478 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother's mother's mother's father
- 2208956 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother's mother's mother's father's father
- 4417913 Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother's mother's mother's father's father's mother
Your father's father's father's father's mother's mother's father's mother's mother's father's mother's father's father's mother's father's mother's mother's mother's mother's father's father's mother, a 20x great-grandmother, is number 4417913.