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
- 496 Your mother's mother's mother's mother's father's father's father's father
- 993 Your mother's mother's mother's mother's father's father's father's father's mother
- 1987 Your mother's mother's mother's mother's father's father's father's father's mother's mother
- 3975 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother
- 7951 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother
- 15902 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father
- 31804 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father
- 63609 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother
- 127219 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother
- 254439 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother's mother
- 508879 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother
- 1017759 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother's mother
- 2035519 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother's mother's mother
- 4071038 Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother's mother's mother's father
Your mother's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother's mother's mother's father, a 19x great-grandfather, is number 4071038.