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
- 249 Your mother's mother's mother's mother's father's father's mother
- 499 Your mother's mother's mother's mother's father's father's mother's mother
- 999 Your mother's mother's mother's mother's father's father's mother's mother's mother
- 1998 Your mother's mother's mother's mother's father's father's mother's mother's mother's father
- 3997 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother
- 7995 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother
- 15990 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father
- 31980 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father
- 63961 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother
- 127922 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father
- 255845 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother
- 511691 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother
- 1023382 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father
- 2046764 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father
- 4093529 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother
- 8187059 Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother
Your mother's mother's mother's mother's father's father's mother's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father's mother's mother, a 20x great-grandmother, is number 8187059.