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
- 15 Your mother's mother's mother
- 31 Your mother's mother's mother's mother
- 62 Your mother's mother's mother's mother's father
- 124 Your mother's mother's mother's mother's father's father
- 248 Your mother's mother's mother's mother's father's father's father
- 497 Your mother's mother's mother's mother's father's father's father's mother
- 995 Your mother's mother's mother's mother's father's father's father's mother's mother
- 1991 Your mother's mother's mother's mother's father's father's father's mother's mother's mother
- 3983 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother
- 7966 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father
- 15932 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father
- 31864 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father
- 63729 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother
- 127458 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father
- 254916 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father's father
- 509833 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father's father's mother
- 1019666 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father's father's mother's father
- 2039332 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father's father's mother's father's father
- 4078664 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father's father's mother's father's father's father
Your mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's father's father's father's mother's father's father's mother's father's father's father, a 19x great-grandfather, is number 4078664.