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 (opens in a new tab) 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
- 5 Your father's mother
- 11 Your father's mother's mother
- 23 Your father's mother's mother's mother
- 47 Your father's mother's mother's mother's mother
- 94 Your father's mother's mother's mother's mother's father
- 189 Your father's mother's mother's mother's mother's father's mother
- 379 Your father's mother's mother's mother's mother's father's mother's mother
- 759 Your father's mother's mother's mother's mother's father's mother's mother's mother
- 1518 Your father's mother's mother's mother's mother's father's mother's mother's mother's father
- 3037 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother
- 6075 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother
- 12150 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father
- 24301 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother
- 48603 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother
- 97207 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother
- 194415 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother
- 388831 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother
- 777663 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother
- 1555327 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's mother
- 3110654 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's mother's father
- 6221309 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's mother's father's mother
- 12442619 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's mother's father's mother's mother
- 24885239 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's mother
- 49770479 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother'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 mother
- 99540958 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother'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 mother's father
- 199081917 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother'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 mother's father's mother
- 398163835 Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother'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 mother's father's mother's mother
Your father's mother's mother's mother's mother's father's mother's mother's mother's father's mother's mother'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 mother's father's mother's mother, a 26x great-grandmother, is number 398163835.