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
- 6 Your mother's father
- 12 Your mother's father's father
- 24 Your mother's father's father's father
- 48 Your mother's father's father's father's father
- 97 Your mother's father's father's father's father's mother
- 195 Your mother's father's father's father's father's mother's mother
- 390 Your mother's father's father's father's father's mother's mother's father
- 781 Your mother's father's father's father's father's mother's mother's father's mother
- 1563 Your mother's father's father's father's father's mother's mother's father's mother's mother
- 3126 Your mother's father's father's father's father's mother's mother's father's mother's mother's father
- 6253 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother
- 12507 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother
- 25014 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father
- 50028 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father
- 100057 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother
- 200115 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother
- 400231 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother
- 800463 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother
- 1600927 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's mother
- 3201855 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's mother's mother
- 6403710 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's mother's mother's father
- 12807421 Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother
Your mother's father's father's father's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's mother's mother's father's mother, a 21x great-grandmother, is number 12807421.