Have you ever wondered how many ancestors you have? What about the number of living relatives? Where do your ancestors come from? What does your surname mean?
Finding answers to these questions can be fun. Even better, these answers help you connect with your family, both living and deceased, as you learn more about them—and about you.
How Many Ancestors Do I Have?
First, let’s define ancestor. An ancestor is any person from whom you are descended. Your great-grandparents are your ancestors, and their parents are too, and their parents, as far back as you can go.
The formula for calculating the number of your ancestors is simple: as you might expect, the number doubles with every generation. You have 2 parents. Each of your parents has 2 parents, for a total of 4. They each have 2 parents for a total of 8, and so on. The table below shows how the numbers add up.
For those of you who want an actual formula, use 2n=X. Replace n with the number of generations back from you, and X will be the number of ancestors in that generation. Note that on the fan chart image, a hyphen should follow "1st," "2nd," "3rd," "4th," and so on.
| Generation Back from You | Ancestors | Number of Ancestors in this Generation | Cumulative Total Ancestors |
| 1 | Parents | 2 | 2 |
| 2 | Grandparents | 4 | 6 |
| 3 | Great-grandparents | 8 | 14 |
| 4 | 2nd-great-grandparents | 16 | 30 |
| 5 | 3rd-great-grandparents | 32 | 62 |
| 6 | 4th-great-grandparents | 64 | 126 |
| 7 | 5th-great-grandparents | 128 | 254 |
| 8 | 6th-great-grandparents | 256 | 510 |
| 9 | 7th-great-grandparents | 512 | 1,022 |
| 10 | 8th-great-grandparents | 1,024 | 2,046 |
| 11 | 9th-great-grandparents | 2,048 | 4,094 |
| 12 | 10th-great-grandparents | 4,096 | 8,190 |
By the time you’ve gotten back to your 10th-great-grandparents, you could have around 8,000 ancestors!
However, a possible wrinkle affects these calculations. Depending on the time and culture, cousins may have married cousins, making a branch on your tree “collapse,” so to speak. In other words, 2 of your ancestors in the same generation could have had the same grandparents, so their ancestral lines converge. The further you go back in time, the more a collapse is likely. Still, the formula gives you a pretty good approximation, especially for more recent generations.
How Many Cousins Do I Have?
While an ancestor is any person from whom you’re descended, a cousin is any descendant of an ancestor who is not also your sibling. So, for example, any descendant of your 3rd-great-grandparents who is not your sibling is a cousin!
Cousin relationships can get complicated. You can have first, second, and third cousins—and more. Cousins can also be designated as “removed,” referring to their distance in generations from you. Explaining cousin relationships in detail is beyond our current scope, but read this article if you’d like to learn more.
How can you tell how many cousins you have? You could count them—but for most of us that isn’t realistic. So once again, we can turn to a formula to give us a pretty good approximation.
This formula is simplest and most accurate if we start calculating from one set of grandparents. This means we're really figuring out how many cousins you might have in one ancestral line. For any given generation back from you, use fc-1=X, where f is the number of families in that generation, c is the number of children in each family, and X is the number of cousins in that generation.
Note that the formula has you subtract 1, because 1 of the children in each generation would have been your direct ancestor, not your cousin. Also, we have to use an approximate number of children—because otherwise we're back to counting. You might choose to use a different approximation than the one in our example below, depending on your family's history and culture.
For the sake of illustration, let’s choose a set of your 8th-great-grandparents—they would be 10 generations back from you. Let’s assume that the couples in each generation had 4 children. (In reality, some will have had more and some less, but 4 is a reasonable average.) Here’s how the numbers play out.
| Generations Back from You | Families | Number of Cousins You Have in This Generation* | Cumulative Number of Cousins Calculated |
| 10 | 1 couple (your 8th-great-grandparents) with 4 children | 3 | 3 |
| 9 | 4 couples with 4 children each | 15 | 18 |
| 8 | 16 couples with 4 children each | 63 | 81 |
| 7 | 64 couples with 4 children each | 255 | 336 |
| 6 | 256 couples with 4 children each | 1023 | 1,359 |
| 5 | 1,024 couples with 4 children each | 4095 | 5,454 |
| 4 | 4,096 couples with 4 children each | 16,383 | 21,837 |
| 3 | 16,384 couples with 4 children each | 65,535 | 87,372 |
| 2 | 65,536 couples with 4 children each | 262,143 | 349,515 |
| 1 | 262,144 couples with 4 children each | 1,048,575 | 1,398,090 |
*Remember that in each generation, 1 is subtracted from the total number of children because 1 of those children is your direct ancestor, not your cousin.
Again, some of the lines will converge when cousins marry cousins. But starting with just 1 ancestral couple 10 generations back, you could have somewhere around a million cousins on that line in your generation, and around 1.4 million total on that line! If you were to calculate the descendants of all your ancestors, you can see that the numbers would be exponentially greater.
This calculation leads to the next question.
How Many People on Earth Am I Related To?
The answer to this question is actually pretty simple: All of them! Many faith traditions, such as Christianity, Judaism, and Islam, hold that a common ancestral couple began the human race. And scientific research supports that humans descended from common ancestors. The cousin relationships between 2 living people may be distant (for example, someone might be your 35th cousin 14 times removed), but still, everyone you meet—including the woman at the store or the man on the bus—is your cousin. We’re all family.
Note: When defining "relation" and "cousin," some fields of science and genealogy may use a narrower definition. For example, a DNA test can help you find relatives by finding cousin matches, people whose DNA matches yours significantly. For more information, visit ISOGG's article on cousin statistics or this video from Family History Fanatics.
What Countries Do My Ancestors Come From?
Numbers can be intriguing, but what about the ethnicities that combined to create the unique person you are? Pedigree Pie, a free app created by the BYU Family History Technology Lab, uses your information in Family Tree to show where your ancestors came from.
Of course, the more accurate and complete your family tree is, the more accurate and complete your pedigree pie will be.
Other Fun Questions
Here are some more questions that will help you discover more about your family.
What does your surname mean?
Visit the FamilySearch surname search page to find out what your surname means. You’ll also see maps showing the most common birthplaces of people in Family Tree with that surname. You can look up your own surname or any other.
If you want more information about the surnames in your family, check out Surname Distribution Maps.
Who looks like you?
Has someone told you that you’re a younger version of your grandfather? Do you have your great-aunt’s nose? Upload a photo of yourself to FamilySearch Compare-A-Face to see which ancestors you resemble the most. You might be surprised!
What was happening the year a family member was born?
Visit the All About Me page to find out what happened during a given year. The page will first show the year you were born, but you can click View a Different Year to enter another year or choose an ancestor from Family Tree. Learn about the top news stories that year, the top technology breakthroughs, and even the cost of a gallon of gas!
Want to play some games?
Try the family history versions of 2 popular game shows: Wheel of Family Fortune and Geneopardy. These apps use information in Family Tree to create games your family can play together to learn more about generations past.
Visit the Family History Activities page to find even more answers about your family.
There’s More to Discover!
Let’s end with a final question. How many names are in FamilySearch Family Tree, the shared pedigree we’re building of the human family? According to FamilySearch’s 2021 review, the number of names at the end of 2021 was 1.38 billion! And it’s growing all the time.
You can help build the shared tree. If you don’t already have an account, you can create one for free. Your account also gives you free access to billions of historical records to help you learn more about your family. In addition, you can connect with living family members and share photos and stories of your ancestors.
Explore FamilySearch.org today, and see what else you can discover about your family!
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