# What is the Greatest Common Factor of 8 and 18?

Greatest common factor (GCF) of 8 and 18 is **2**.

GCF(8,18) = 2

We will now calculate the prime factors of **8 and 18**, than find the greatest common factor *(greatest common divisor (gcd))* of the numbers by matching the biggest common factor of 8 and 18.

## How to find the GCF of 8 and 18?

We will first find the prime factorization of 8 and 18. After we will calculate the factors of 8 and 18 and find the biggest common factor number .

### Step-1: Prime Factorization of 8

Prime factors of 8 are 2. Prime factorization of **8** in exponential form is:

8 = 2^{3}

### Step-2: Prime Factorization of 18

Prime factors of 18 are 2, 3. Prime factorization of **18** in exponential form is:

18 = 2^{1} × 3^{2}

### Step-3: Factors of 8

List of positive integer factors of 8 that divides 8 without a remainder.

1, 2, 4

### Step-4: Factors of 18

List of positive integer factors of 18 that divides 8 without a remainder.

1, 2, 3, 6, 9

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 8 and 18. The biggest common factor number is the **GCF** number.

So the **greatest common factor 8 and 18** is **2**.

Also check out the Least Common Multiple of 8 and 18