---
title: "Cousin Relationship Calculator & Chart | Kinfolk Canvas"
description: "Name the exact relationship between two relatives, from great-aunts to third cousins twice removed, with a diagram, a cousin chart and shared DNA."
url: https://kinfolkcanvas.sbs/cousin-calculator/
---

# Cousin relationship calculator

Count how many generations each person sits below the ancestor you both descend from. The calculator names the relationship both ways, draws it, and shows the expected share of DNA.

You are Maria’s first cousin once removed.

Also written: 1st cousin 1× removed

The shared ancestors (usually a couple): your grandparents and Maria’s great-grandparents.

“Once removed” means Maria is 1 generation further from the common ancestor than you.

- **Expected shared DNA**: 6.25% (1/16)

Each step down is one generation. Grey dotted lines stand for generations not drawn.

## Cousin chart

Rows show how person A descends from the common ancestor, columns how person B does, and each square says what B is to A. Pick a square to load it into the calculator.

|  | Common ancestor | Child | Grandchild | Great-grandchild | 2nd great-grandchild | 3rd great-grandchild | 4th great-grandchild | 5th great-grandchild |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Common ancestor |  |  |  |  |  |  |  |  |
| Child |  |  |  |  |  |  |  |  |
| Grandchild |  |  |  |  |  |  |  |  |
| Great-grandchild |  |  |  |  |  |  |  |  |
| 2nd great-grandchild |  |  |  |  |  |  |  |  |
| 3rd great-grandchild |  |  |  |  |  |  |  |  |
| 4th great-grandchild |  |  |  |  |  |  |  |  |
| 5th great-grandchild |  |  |  |  |  |  |  |  |

## How to count generations

Find the closest ancestor (or ancestral couple) that both people descend from. For each person, count the steps down: a child is 1, a grandchild 2, a great-grandchild 3. Your first cousin shares your grandparents, so you are both 2 generations down.

The rule behind cousins is simple. The cousin number is the smaller of the two counts minus one. “Removed” is the difference between the counts: how many generations apart the two people are. Your parent’s first cousin, at 2 and 3 generations, is your first cousin once removed.

## Aunts, nieces and the greats

When one person is just 1 generation down, they are a sibling of the other’s parent, grandparent and so on: an aunt or uncle, then a great-aunt. Many genealogists prefer “grandaunt” for the parent’s aunt, so both are shown. Direct ancestors and descendants have no cousin number at all.

## Expected shared DNA

The percentage is Sewall Wright’s coefficient of relationship: each line of descent through a common ancestor halves at every step, and full relatives descend through two ancestors (a couple) while half relatives descend through one. It is an average. Real shared DNA varies, and distant cousins may share none.

## Sources

- Wright S. Coefficients of inbreeding and relationship. *The American Naturalist* 1922;56(645):330–338. [doi:10.1086/279872](https://doi.org/10.1086/279872)

## Questions

**Is a second cousin the same as a first cousin once removed?**

No. Second cousins share great-grandparents and are the same generation. A first cousin once removed is your parent’s first cousin or your first cousin’s child.

**What is a double cousin?**

When two siblings marry two siblings, their children share both sets of grandparents. They are double first cousins, and on average share about twice the DNA of ordinary first cousins.

**Does the tool work for in-laws?**

No. It names blood relationships only. A relative by marriage has no common ancestor with you, so there is no cousin number to calculate.