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
- 54 Your mother's father's mother's mother's father
- 109 Your mother's father's mother's mother's father's mother
- 218 Your mother's father's mother's mother's father's mother's father
- 436 Your mother's father's mother's mother's father's mother's father's father
- 872 Your mother's father's mother's mother's father's mother's father's father's father
- 1745 Your mother's father's mother's mother's father's mother's father's father's father's mother
- 3491 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother
- 6983 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother
- 13967 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother
- 27934 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father
- 55869 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother
- 111739 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother
- 223479 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother
- 446959 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's mother
- 893919 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's mother's mother
- 1787839 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's mother's mother's mother
- 3575678 Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father
Your mother's father's mother's mother's father's mother's father's father's father's mother's mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father, a 19x great-grandfather, is number 3575678.