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
- 96 Your mother's father's father's father's father's father
- 192 Your mother's father's father's father's father's father's father
- 385 Your mother's father's father's father's father's father's father's mother
- 771 Your mother's father's father's father's father's father's father's mother's mother
- 1543 Your mother's father's father's father's father's father's father's mother's mother's mother
- 3087 Your mother's father's father's father's father's father's father's mother's mother's mother's mother
- 6175 Your mother's father's father's father's father's father's father's mother's mother's mother's mother's mother
- 12351 Your mother's father's father's father's father's father's father's mother's mother's mother's mother's mother's mother
- 24703 Your mother'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 mother
- 49406 Your mother'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 mother's father
- 98813 Your mother'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 mother's father's mother
- 197627 Your mother'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 mother's father's mother's mother
- 395255 Your mother'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 mother's father's mother's mother's mother
- 790510 Your mother'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 mother's father's mother's mother's mother's father
Your mother'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 mother's father's mother's mother's mother's father, a 17x great-grandfather, is number 790510.