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
- 13 Your mother's father's mother
- 27 Your mother's father's mother's mother
- 54 Your mother's father's mother's mother's father
- 109 Your mother's father's mother's mother's father's mother
- 219 Your mother's father's mother's mother's father's mother's mother
- 438 Your mother's father's mother's mother's father's mother's mother's father
- 877 Your mother's father's mother's mother's father's mother's mother's father's mother
- 1755 Your mother's father's mother's mother's father's mother's mother's father's mother's mother
- 3510 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father
- 7020 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father
- 14040 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father
- 28080 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father
- 56161 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother
- 112323 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother
- 224647 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother's mother
- 449294 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother's mother's father
- 898589 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother's mother's father's mother
- 1797178 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother's mother's father's mother's father
- 3594356 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother's mother's father's mother's father's father
Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's father's father's mother's mother's mother's father's mother's father's father, a 19x great-grandfather, is number 3594356.