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
- 30 Your mother's mother's mother's father
- 61 Your mother's mother's mother's father's mother
- 123 Your mother's mother's mother's father's mother's mother
- 247 Your mother's mother's mother's father's mother's mother's mother
- 495 Your mother's mother's mother's father's mother's mother's mother's mother
- 991 Your mother's mother's mother's father's mother's mother's mother's mother's mother
- 1983 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother
- 3966 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father
- 7932 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father
- 15864 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father
- 31728 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father
- 63456 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father
- 126913 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father's mother
- 253827 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father's mother's mother
- 507654 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father's mother's mother's father
- 1015309 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father's mother's mother's father's mother
- 2030619 Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father's mother's mother's father's mother's mother
Your mother's mother's mother's father's mother's mother's mother's mother's mother's mother's father's father's father's father's father's mother's mother's father's mother's mother, a 18x great-grandmother, is number 2030619.