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
- 30 Your mother's mother's mother's father
- 61 Your mother's mother's mother's father's mother
- 122 Your mother's mother's mother's father's mother's father
- 245 Your mother's mother's mother's father's mother's father's mother
- 491 Your mother's mother's mother's father's mother's father's mother's mother
- 983 Your mother's mother's mother's father's mother's father's mother's mother's mother
- 1967 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother
- 3934 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father
- 7869 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother
- 15739 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother
- 31478 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father
- 62957 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother
- 125915 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother
- 251830 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother's father
- 503661 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's mother
- 1007323 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's mother's mother
- 2014646 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's mother's mother's father
- 4029292 Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father
Your mother's mother's mother's father's mother's father's mother's mother's mother's mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father, a 19x great-grandfather, is number 4029292.