# Greatest Common Divisor Calculator

Created by Komal Rafay
Reviewed by Steven Wooding
Last updated: Mar 10, 2023

The greatest common divisor calculator is here to make mathematics and hence life easier for you. It will help you determine not only the greatest common divisor but also the common divisors among numbers.

You'll get to learn about the following:

• What is the greatest common divisor (GCD)?
• Applications of the greatest common divisor.

## What is greatest common divisor?

In mathematics, the greatest common divisor (GCD) of two or more numbers is the largest number that divides all the numbers in the set without leaving a remainder. GCD is an important concept that plays a crucial role in various fields, including number theory, cryptography, computer science, and engineering.

## The greatest common divisor calculator

Our greatest common divisor calculator is as easy as it gets. It will not only help you determine the greatest common divisor for up to 15 integers, but it will do it using five different algorithms.

Let's take a look at the steps involved in the tool.

1. Enter the 1st and second numbers.

2. The tool displays the greatest common divisor of the two numbers.

3. You may enter up to 15 numbers.

4. There is also the option to have an elaborate solution through 5 different algorithms. You may select any of your liking from the "step-by-step solution" section.

a. List of factors.
b. Prime factorization.
c. Euclidean algorithm.
d. Binary (Stein's) algorithm.
e. Upside down division.

For instance, you input $15$, $45$ and $75$. The estimated greatest common divisor among the three is $15$. The common factors for the input numbers are 1, 3, 5, and 15. But the highest among them is 15. Hence it is the GCD (greatest common divisor).

## Applications of greatest common divisor

The concept of the greatest common divisor has a vast array of applications in many fields of science and has implications in the real world. Let's take a look at a few:

Simplifying fractions: The greatest common divisor reduces a fraction to its simplest form by dividing the numerator and denominator by their GCD.

Euclidean algorithm: Euclidean algorithm is a method for finding the GCD of two numbers and is one of the oldest algorithms known to mathematics.

Cryptography: GCD finds its applications in public key cryptography systems such as the RSA algorithm, where the system's security relies on the difficulty of finding the GCD of large numbers.

Engineering: The greatest common divisor helps design gears and other mechanical systems where precise ratios between rotating parts are important.

Linear Diophantine equations: Solving linear Diophantine equations uses the greatest common divisor as a base. These equations involve two or more variables and integer solutions.

Number theory: The GCD is a fundamental concept in number theory used to study the properties of numbers and their relationships with other numbers.

## More to explore the number theory

How about exploring some more tools from the factors and divisors domain?

## FAQ

### What is the greatest common divisor of {6,9,12}?

The greatest common divisor of {6,9,12} is 3.

There are multiple methods to choose from to determine the greatest common divisor:

• List of factors;
• Prime factorization;
• Euclidean algorithm;
• Binary algorithm; and
• Upside-down division.

### How can I calculate the GCD of any 2 numbers?

There are many methods to choose from. Let's focus on the simplest for two numbers.

1. List all the divisors of the first number.
2. List all the divisors of the second number.
3. Separate out the common divisors among them.
4. The greatest common divisor is the largest among these selected common divisors.
Komal Rafay
Data (you may enter up to 15 integer numbers)
#1
#2
Step by step solution?
Choose method:
None
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