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 (opens in a new tab) 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
- 2 Your father
- 4 Your father's father
- 9 Your father's father's mother
- 19 Your father's father's mother's mother
- 38 Your father's father's mother's mother's father
- 76 Your father's father's mother's mother's father's father
- 152 Your father's father's mother's mother's father's father's father
- 305 Your father's father's mother's mother's father's father's father's mother
- 611 Your father's father's mother's mother's father's father's father's mother's mother
- 1223 Your father's father's mother's mother's father's father's father's mother's mother's mother
- 2447 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother
- 4895 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother
- 9791 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother
- 19583 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother
- 39166 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother's father
- 78333 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother's father's mother
- 156667 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother's father's mother's mother
- 313334 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father
- 626669 Your father's father's mother's mother's father's father's father's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother
- 1253339 Your father's father's mother's mother's father's father's father'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
- 2506679 Your father's father's mother's mother's father's father's father'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's mother
- 5013359 Your father's father's mother's mother's father's father's father'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's mother's mother
- 10026719 Your father's father's mother's mother's father's father's father'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's mother's mother's mother
- 20053439 Your father's father's mother's mother's father's father's father'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's mother's mother's mother's mother
- 40106879 Your father's father's mother's mother's father's father's father'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's mother's mother's mother's mother's mother
Your father's father's mother's mother's father's father's father'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's mother's mother's mother's mother's mother, a 23x great-grandmother, is number 40106879.