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
- 2 Your father
- 5 Your father's mother
- 11 Your father's mother's mother
- 22 Your father's mother's mother's father
- 44 Your father's mother's mother's father's father
- 88 Your father's mother's mother's father's father's father
- 177 Your father's mother's mother's father's father's father's mother
- 355 Your father's mother's mother's father's father's father's mother's mother
- 711 Your father's mother's mother's father's father's father's mother's mother's mother
- 1423 Your father's mother's mother's father's father's father's mother's mother's mother's mother
- 2847 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother
- 5695 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother
- 11390 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father
- 22780 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father's father
- 45560 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father's father's father
- 91121 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father's father's father's mother
- 182243 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother
- 364486 Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother's father
Your father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's father's father's father's mother's mother's father, a 16x great-grandfather, is number 364486.