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
- 4 Your father's father
- 8 Your father's father's father
- 16 Your father's father's father's father
- 32 Your father's father's father's father's father
- 65 Your father's father's father's father's father's mother
- 131 Your father's father's father's father's father's mother's mother
- 262 Your father's father's father's father's father's mother's mother's father
- 525 Your father's father's father's father's father's mother's mother's father's mother
- 1051 Your father's father's father's father's father's mother's mother's father's mother's mother
- 2102 Your father's father's father's father's father's mother's mother's father's mother's mother's father
- 4205 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother
- 8410 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father
- 16821 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father's mother
- 33643 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father's mother's mother
- 67286 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father's mother's mother's father
- 134572 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father's mother's mother's father's father
- 269145 Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father's mother's mother's father's father's mother
Your father's father's father's father's father's mother's mother's father's mother's mother's father's mother's father's mother's mother's father's father's mother, a 16x great-grandmother, is number 269145.