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
- 2 Your father
- 5 Your father's mother
- 11 Your father's mother's mother
- 22 Your father's mother's mother's father
- 45 Your father's mother's mother's father's mother
- 90 Your father's mother's mother's father's mother's father
- 180 Your father's mother's mother's father's mother's father's father
- 361 Your father's mother's mother's father's mother's father's father's mother
- 723 Your father's mother's mother's father's mother's father's father's mother's mother
- 1447 Your father's mother's mother's father's mother's father's father's mother's mother's mother
- 2895 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother
- 5791 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother
- 11583 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother
- 23166 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father
- 46333 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother
- 92667 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother
- 185335 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother
- 370670 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father
- 741341 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's mother
- 1482683 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother
- 2965366 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father
- 5930733 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother
- 11861467 Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother
Your father's mother's mother's father's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother, a 21x great-grandmother, is number 11861467.