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
- 27 Your mother's father's mother's mother
- 54 Your mother's father's mother's mother's father
- 109 Your mother's father's mother's mother's father's mother
- 219 Your mother's father's mother's mother's father's mother's mother
- 438 Your mother's father's mother's mother's father's mother's mother's father
- 877 Your mother's father's mother's mother's father's mother's mother's father's mother
- 1755 Your mother's father's mother's mother's father's mother's mother's father's mother's mother
- 3510 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father
- 7020 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father
- 14041 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother
- 28083 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother
- 56167 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother
- 112335 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother
- 224670 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father
- 449340 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father
- 898681 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother
- 1797363 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's mother
- 3594727 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's mother's mother
- 7189455 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother
- 14378911 Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother's mother
Your mother's father's mother's mother's father's mother's mother's father's mother's mother's father's father's mother's mother's mother's mother's father's father's mother's mother's mother's mother's mother, a 21x great-grandmother, is number 14378911.