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
- 63 Your mother's mother's mother's mother's mother
- 127 Your mother's mother's mother's mother's mother's mother
- 254 Your mother's mother's mother's mother's mother's mother's father
- 509 Your mother's mother's mother's mother's mother's mother's father's mother
- 1019 Your mother's mother's mother's mother's mother's mother's father's mother's mother
- 2039 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother
- 4078 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father
- 8156 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father
- 16312 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father
- 32624 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father
- 65249 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's mother
- 130499 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's mother's mother
- 260999 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's mother's mother's mother
- 521999 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's mother's mother's mother's mother
- 1043998 Your mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's father's father's father's mother's mother's mother's mother's father
- 2087996 Your mother's mother's mother's mother's mother's mother's father'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
- 4175992 Your mother's mother's mother's mother's mother's mother's father'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 father
- 8351984 Your mother's mother's mother's mother's mother's mother's father'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 father's father
Your mother's mother's mother's mother's mother's mother's father'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 father's father, a 20x great-grandfather, is number 8351984.