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
- 454 Your mother's mother's father's father's father's mother's mother's father
- 909 Your mother's mother's father's father's father's mother's mother's father's mother
- 1819 Your mother's mother's father's father's father's mother's mother's father's mother's mother
- 3639 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother
- 7279 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother
- 14559 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother
- 29118 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father
- 58237 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother
- 116474 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father
- 232949 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother
- 465898 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father
- 931797 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father's mother
- 1863594 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father's mother's father
- 3727189 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father's mother's father's mother
- 7454379 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father's mother's father's mother's mother
- 14908758 Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father's mother's father's mother's mother's father
Your mother's mother's father's father's father's mother's mother's father's mother's mother's mother's mother's mother's father's mother's father's mother's father's mother's father's mother's mother's father, a 21x great-grandfather, is number 14908758.