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
- 17 Your father's father's father's mother
- 35 Your father's father's father's mother's mother
- 70 Your father's father's father's mother's mother's father
- 141 Your father's father's father's mother's mother's father's mother
- 283 Your father's father's father's mother's mother's father's mother's mother
- 566 Your father's father's father's mother's mother's father's mother's mother's father
- 1132 Your father's father's father's mother's mother's father's mother's mother's father's father
- 2264 Your father's father's father's mother's mother's father's mother's mother's father's father's father
- 4529 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother
- 9059 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother
- 18118 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father
- 36236 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father
- 72473 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother
- 144947 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother
- 289895 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother
- 579791 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother's mother
- 1159582 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother's mother's father
- 2319164 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother's mother's father's father
- 4638329 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother
- 9276658 Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father
Your father's father's father's mother's mother's father's mother's mother's father's father's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's father, a 21x great-grandfather, is number 9276658.