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
- 13 Your mother's father's mother
- 27 Your mother's father's mother's mother
- 54 Your mother's father's mother's mother's father
- 109 Your mother's father's mother's mother's father's mother
- 218 Your mother's father's mother's mother's father's mother's father
- 437 Your mother's father's mother's mother's father's mother's father's mother
- 875 Your mother's father's mother's mother's father's mother's father's mother's mother
- 1751 Your mother's father's mother's mother's father's mother's father's mother's mother's mother
- 3503 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother
- 7006 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father
- 14012 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father
- 28024 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father
- 56049 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother
- 112099 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother
- 224199 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother's mother
- 448399 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother
- 896799 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother
- 1793599 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother
- 3587199 Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother
Your mother's father's mother's mother's father's mother's father's mother's mother's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother, a 19x great-grandmother, is number 3587199.