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
- 44 Your father's mother's mother's father's father
- 89 Your father's mother's mother's father's father's mother
- 179 Your father's mother's mother's father's father's mother's mother
- 358 Your father's mother's mother's father's father's mother's mother's father
- 716 Your father's mother's mother's father's father's mother's mother's father's father
- 1433 Your father's mother's mother's father's father's mother's mother's father's father's mother
- 2867 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother
- 5735 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother
- 11470 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father
- 22941 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother
- 45883 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother
- 91767 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's mother
- 183534 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's mother's father
- 367069 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's mother's father's mother
- 734139 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's mother's father's mother's mother
- 1468278 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father
- 2936557 Your father's mother's mother's father's father's mother's mother's father's father's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother
- 5873115 Your father's mother's mother's father's father's mother's mother's father's father'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 father's mother's mother's father's father'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 20x great-grandmother, is number 5873115.