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
- 6 Your mother's father
- 13 Your mother's father's mother
- 27 Your mother's father's mother's mother
- 55 Your mother's father's mother's mother's mother
- 111 Your mother's father's mother's mother's mother's mother
- 222 Your mother's father's mother's mother's mother's mother's father
- 445 Your mother's father's mother's mother's mother's mother's father's mother
- 891 Your mother's father's mother's mother's mother's mother's father's mother's mother
- 1782 Your mother's father's mother's mother's mother's mother's father's mother's mother's father
- 3564 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father
- 7129 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother
- 14259 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother
- 28519 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's mother
- 57038 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's mother's father
- 114077 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's mother's father's mother
- 228155 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother
- 456310 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's father
- 912620 Your mother's father's mother's mother's mother's mother's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father
- 1825240 Your mother's father's mother's mother's mother's mother's father'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
- 3650481 Your mother's father's mother's mother's mother's mother's father'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 mother
Your mother's father's mother's mother's mother's mother's father'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 mother, a 19x great-grandmother, is number 3650481.