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
- 29 Your mother's mother's father's mother
- 59 Your mother's mother's father's mother's mother
- 118 Your mother's mother's father's mother's mother's father
- 237 Your mother's mother's father's mother's mother's father's mother
- 475 Your mother's mother's father's mother's mother's father's mother's mother
- 950 Your mother's mother's father's mother's mother's father's mother's mother's father
- 1900 Your mother's mother's father's mother's mother's father's mother's mother's father's father
- 3800 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father
- 7601 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother
- 15202 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father
- 30405 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother
- 60811 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother
- 121623 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother
- 243247 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother
- 486494 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother's father
- 972988 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother's father's father
- 1945977 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother's father's father's mother
- 3891955 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother's father's father's mother's mother
- 7783910 Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother's father's father's mother's mother's father
Your mother's mother's father's mother's mother's father's mother's mother's father's father's father's mother's father's mother's mother's mother's mother's father's father's mother's mother's father, a 20x great-grandfather, is number 7783910.