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
- 7 Your mother's mother
- 15 Your mother's mother's mother
- 31 Your mother's mother's mother's mother
- 63 Your mother's mother's mother's mother's mother
- 127 Your mother's mother's mother's mother's mother's mother
- 255 Your mother's mother's mother's mother's mother's mother's mother
- 511 Your mother's mother's mother's mother's mother's mother's mother's mother
- 1023 Your mother's mother's mother's mother's mother's mother's mother's mother's mother
- 2047 Your mother's mother's mother's mother's mother's mother's mother's mother's mother's mother
- 4094 Your mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father
- 8189 Your mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother
- 16379 Your mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother
- 32758 Your mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father
- 65517 Your mother's mother's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother
- 131035 Your mother's mother's mother'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
- 262071 Your mother's mother's mother'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
- 524143 Your mother's mother's mother'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
- 1048287 Your mother's mother's mother'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
- 2096574 Your mother's mother's mother'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 father
- 4193149 Your mother's mother's mother'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 father's mother
Your mother's mother's mother'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 father's mother, a 19x great-grandmother, is number 4193149.