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
- 4 Your father's father
- 9 Your father's father's mother
- 19 Your father's father's mother's mother
- 38 Your father's father's mother's mother's father
- 76 Your father's father's mother's mother's father's father
- 152 Your father's father's mother's mother's father's father's father
- 305 Your father's father's mother's mother's father's father's father's mother
- 611 Your father's father's mother's mother's father's father's father's mother's mother
- 1222 Your father's father's mother's mother's father's father's father's mother's mother's father
- 2444 Your father's father's mother's mother's father's father's father's mother's mother's father's father
- 4888 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father
- 9777 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father's mother
- 19555 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father's mother's mother
- 39111 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father's mother's mother's mother
- 78223 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father's mother's mother's mother's mother
- 156447 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother
- 312895 Your father's father's mother's mother's father's father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother
- 625790 Your father's father's mother's mother's father's father's 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
- 1251580 Your father's father's mother's mother's father's father's 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
- 2503160 Your father's father's mother's mother's father's father's 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
- 5006320 Your father's father's mother's mother's father's father's 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 father
Your father's father's mother's mother's father's father's 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 father, a 20x great-grandfather, is number 5006320.