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
- 57 Your mother's mother's father's father's mother
- 115 Your mother's mother's father's father's mother's mother
- 231 Your mother's mother's father's father's mother's mother's mother
- 463 Your mother's mother's father's father's mother's mother's mother's mother
- 926 Your mother's mother's father's father's mother's mother's mother's mother's father
- 1852 Your mother's mother's father's father's mother's mother's mother's mother's father's father
- 3705 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother
- 7410 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father
- 14820 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father
- 29641 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother
- 59283 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother
- 118567 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother's mother
- 237135 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother's mother's mother
- 474271 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother's mother's mother's mother
- 948542 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother's mother's mother's mother's father
- 1897085 Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother's mother's mother's mother's father's mother
Your mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father's father's mother's mother's mother's mother's mother's father's mother, a 18x great-grandmother, is number 1897085.