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
- 6 Your mother's father
- 12 Your mother's father's father
- 24 Your mother's father's father's father
- 49 Your mother's father's father's father's mother
- 98 Your mother's father's father's father's mother's father
- 196 Your mother's father's father's father's mother's father's father
- 393 Your mother's father's father's father's mother's father's father's mother
- 786 Your mother's father's father's father's mother's father's father's mother's father
- 1573 Your mother's father's father's father's mother's father's father's mother's father's mother
- 3146 Your mother's father's father's father's mother's father's father's mother's father's mother's father
- 6292 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father
- 12584 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father
- 25168 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father
- 50336 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father's father
- 100673 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father's father's mother
- 201347 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father's father's mother's mother
- 402695 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father's father's mother's mother's mother
- 805390 Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father's father's mother's mother's mother's father
Your mother's father's father's father's mother's father's father's mother's father's mother's father's father's father's father's father's mother's mother's mother's father, a 17x great-grandfather, is number 805390.