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
- 5 Your father's mother
- 10 Your father's mother's father
- 21 Your father's mother's father's mother
- 43 Your father's mother's father's mother's mother
- 87 Your father's mother's father's mother's mother's mother
- 174 Your father's mother's father's mother's mother's mother's father
- 349 Your father's mother's father's mother's mother's mother's father's mother
- 699 Your father's mother's father's mother's mother's mother's father's mother's mother
- 1398 Your father's mother's father's mother's mother's mother's father's mother's mother's father
- 2797 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother
- 5595 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother
- 11190 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father
- 22380 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father
- 44761 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother
- 89522 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father
- 179045 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother
- 358091 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother's mother
- 716182 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father
- 1432364 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father
- 2864728 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father's father
- 5729456 Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father's father's father
Your father's mother's father's mother's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's father's mother's mother's father's father's father's father, a 20x great-grandfather, is number 5729456.