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
- 3 Your mother
- 7 Your mother's mother
- 14 Your mother's mother's father
- 28 Your mother's mother's father's father
- 56 Your mother's mother's father's father's father
- 113 Your mother's mother's father's father's father's mother
- 227 Your mother's mother's father's father's father's mother's mother
- 455 Your mother's mother's father's father's father's mother's mother's mother
- 911 Your mother's mother's father's father's father's mother's mother's mother's mother
- 1822 Your mother's mother's father's father's father's mother's mother's mother's mother's father
- 3645 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother
- 7291 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother
- 14583 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother
- 29166 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father
- 58333 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother
- 116666 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father
- 233333 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father's mother
- 466666 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father's mother's father
- 933333 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father's mother's father's mother
- 1866666 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father's mother's father's mother's father
- 3733333 Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father's mother's father's mother's father's mother
Your mother's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's father's mother's father's mother's father's mother, a 19x great-grandmother, is number 3733333.