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
- 28 Your mother's mother's father's father
- 56 Your mother's mother's father's father's father
- 112 Your mother's mother's father's father's father's father
- 225 Your mother's mother's father's father's father's father's mother
- 451 Your mother's mother's father's father's father's father's mother's mother
- 903 Your mother's mother's father's father's father's father's mother's mother's mother
- 1807 Your mother's mother's father's father's father's father's mother's mother's mother's mother
- 3615 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother
- 7231 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother
- 14463 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother
- 28927 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother
- 57855 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother
- 115711 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother
- 231423 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother
- 462846 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father
- 925693 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother
- 1851387 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother
- 3702774 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father
- 7405549 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother
- 14811099 Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's mother
Your mother's mother's father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's mother, a 21x great-grandmother, is number 14811099.