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
- 26 Your mother's father's mother's father
- 52 Your mother's father's mother's father's father
- 104 Your mother's father's mother's father's father's father
- 208 Your mother's father's mother's father's father's father's father
- 416 Your mother's father's mother's father's father's father's father's father
- 832 Your mother's father's mother's father's father's father's father's father's father
- 1664 Your mother's father's mother's father's father's father's father's father's father's father
- 3329 Your mother's father's mother's father's father's father's father's father's father's father's mother
- 6659 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother
- 13319 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother
- 26639 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother
- 53279 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother
- 106559 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother
- 213118 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother's father
- 426237 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother's father's mother
- 852475 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother
- 1704950 Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's father
Your mother's father's mother's father's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother's father's mother's mother's father, a 18x great-grandfather, is number 1704950.