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
- 497 Your mother's mother's mother's mother's father's father's father's mother
- 995 Your mother's mother's mother's mother's father's father's father's mother's mother
- 1991 Your mother's mother's mother's mother's father's father's father's mother's mother's mother
- 3982 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father
- 7964 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father
- 15928 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father
- 31857 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother
- 63715 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother
- 127431 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother
- 254863 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother
- 509727 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother
- 1019454 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's father
- 2038909 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's father's mother
- 4077819 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's father's mother's mother
- 8155638 Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's father's mother's mother's father
Your mother's mother's mother's mother's father's father's father's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's father's mother's mother's father, a 20x great-grandfather, is number 8155638.