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
- 4 Your father's father
- 8 Your father's father's father
- 16 Your father's father's father's father
- 33 Your father's father's father's father's mother
- 67 Your father's father's father's father's mother's mother
- 135 Your father's father's father's father's mother's mother's mother
- 271 Your father's father's father's father's mother's mother's mother's mother
- 543 Your father's father's father's father's mother's mother's mother's mother's mother
- 1087 Your father's father's father's father's mother's mother's mother's mother's mother's mother
- 2175 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother
- 4351 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother
- 8702 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father
- 17405 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother
- 34811 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother
- 69622 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father
- 139245 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother
- 278490 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father
- 556980 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father
- 1113961 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father's mother
- 2227922 Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father's mother's father
Your father's father's father's father's mother's mother's mother's mother's mother's mother's mother's mother's father's mother's mother's father's mother's father's father's mother's father, a 19x great-grandfather, is number 2227922.