How to Use a Cousin Chart to Find Out How Distant Your Cousins Are

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Learn about first cousins, second cousins, once-removed cousins & more

Co-authored by Zina Savva and Elaine Heredia, BA

Last Updated: May 8, 2026 Fact Checked

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What is a cousin chart?

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First, Second, Third & Removed Cousins

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What is a cousin, exactly?

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Cousins Shared DNA

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Video

You probably know who your first cousin is—they're the child of one of your parents' siblings. But what about your second or third cousin? And what about your first cousin, once removed? That's where your family tree starts to get a little confusing! But never fear, because we're here to help you make sense of how your distant relatives are related to you with exclusive insights shared by a mathematics educator. Keep reading to learn what a cousin chart is and how to read one, plus what exactly a cousin is and how much DNA you share with your cousins.

Cousin Chart: Quick Overview

A cousin chart helps you determine how closely you’re related to one of your cousins, like whether they’re your first cousin, second cousin, third cousin, and so on, and whether they’re “removed,” like your first cousin, once removed. To use a cousin chart, all you need to know is which grandparent(s) you and your cousin share.

Section 1 of 4:

What is a cousin chart and how do you read one?

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A cousin chart helps you determine how closely your cousins are related to you. If you've ever wondered exactly how you’re related to a distant cousin, like whether they’re your second cousin, third cousin, and so on, a cousin chart can make it clear. The chart shows your line of grandparents on the horizontal axis and your cousin’s line on the vertical axis. By identifying which grandparent you both share and locating where they intersect on the chart, you can determine exactly how you and your cousin are related.^{[1]
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- To read a cousin chart:
  - Determine which grandparent you and your cousin share. For example, your great-grandparent might be your cousin’s great-great-grandparent.
  - Find your shared grandparent on the horizontal axis.
  - Find your cousin’s shared grandparent on the vertical axis.
  - Find the point on the chart where each shared grandparent’s row or column intersects. If the intersection point says “third cousin,” for example, you and your cousin are third cousins.
Meet the wikiHow Expert

Zina Savva is a mathematics educator and content creator based in Cyprus. She has over 20 years of experience teaching math and a Master’s Degree in Mathematics Education Methodology.

Section 2 of 4:

How First, Second, Third & Removed Cousins Work

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Your cousin's “number” (first, second, and so on) is how far removed they are from your common ancestor. A quick way to count how many generations removed they are is to count the number of "greats" there are in your common ancestor’s title (e.g., “Great-great-grandmother = 2 “greats”), then add 1 to that number.^{[2]
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Research source} As another method, mathematics educator Zina Savva suggests counting how many generations back the common ancestor is and then subtracting by 1 to get the type of cousin.^{[3]
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Zina Savva
Mathematics Educator

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- For example: Imagine your common ancestor is 2 generations back, says Savva. 2 minus 1 equals 1, so you are first cousins.^{[4]
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- Here’s the breakdown of the common types of cousins:
  - Second cousin: Shared great-grandparents (1 "great" + 1 = 2)
    - Using Savva’s method, your great-grandparent is 3 generations back. 3 minus 1 is 2, so you’re second cousins.^{[5]
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  - Third cousin: Shared great-great-grandparents (2 "greats" + 1 = 3)
    - Using Savva’s method, your great-great-grandparent is 4 generations back. 4 minus 1 is 3, so you’re third cousins.^{[6]
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  - Fourth cousin: Shared great-great-great-grandparents (3 "greats" + 1 = 4)
- Note: These methods for calculating how your cousin is related to you only work if you and your cousin are in the same generation. If there is one or more generations between you, you are “removed” cousins (more on that below).
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A cousin who is "removed" from you is separated from you by at least 1 generation. To calculate the type of cousin they are to you, Savva says to look at the difference in how many generations each person is from the common ancestor. For example, if you and your cousin were born 1 generation apart (i.e., the oldest ancestor you share is your grandparent but their great-grandparent), then you have to add "once removed" to their title, because there’s one generation difference.^{[7]
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- If you’re two generations apart (i.e., the oldest ancestor you share is your grandparent and their great-great-grandparent), you’d add “twice removed” to their title, explains Savva.^{[8]
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- As an example, Savva says your parents’ first cousins are one generation above you, and your first cousins’ children are one generation below you. In both cases, you have a difference of 1 generation, so they are your first cousins once removed.^{[9]
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- Pro tip: If one of your parents has a cousin, add "once removed" to their title. This works no matter what number of cousin they are (i.e., first, second, third, etc.). The "once removed" part simply says that they're separated from you by one generation.
  - For example, if your dad has a first cousin, that person is your first cousin, once removed.

Section 3 of 4:

What is a cousin, exactly?

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A cousin is a relative descended from a common ancestor, like a grandparent. This person is most often the child of one of your parents' siblings (i.e., your aunt or uncle), in which case they would be your first cousin. They can also be descended from one of your grandparents' siblings (i.e., your mother or father's aunt or uncle), making them a first cousin to your mother or father and a first cousin, once removed, to you.^{[10]
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- Not sure who your relatives are? Read our article on "How to Trace Genealogy"!

Section 4 of 4:

How much DNA do cousins share?

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First cousins share roughly 12.5% DNA, whereas second cousins share 3.125%. By looking at how much DNA you and your cousin share from your common ancestor, you can understand just how closely related (or not) you are. As a reminder, your first cousins are the children of your parents' siblings, and you also share the same grandparents. With them, you share about 12.5% DNA. That percentage decreases the further you're removed from your common ancestor. For example, you and your second cousin (with whom you share the same set of great-grandparents) share only 3.125% DNA. Third cousins (with the same great-great-grandparents) share 0.781%.^{[11]
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- For comparison, siblings share around 50% of their DNA because they have the same mother and father.
- Did you know? Former U.S. presidents Barack Obama and George W. Bush are 10th cousins, once removed!^{[12]
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