GCF for 18 and 108

What is the Greatest common Divisor of 18 and 108?

Answer: GCF of 18 and 108 is 18

(Eighteen)

Finding GCF for 18 and 108 using all factors (divisors) listing

The first method to find GCF for numbers 18 and 108 is to list all factors for both numbers and pick the highest common one:

All factors of 18: 1, 2, 3, 6, 9, 18

All factors of 108: 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108

So the Greatest Common Factor for 18 and 108 is 18

Finding GCF for 18 and 108 by Prime Factorization

The second method to find GCF for numbers 18 and 108 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 18: 2, 3, 3

All Prime Factors of 108: 2, 2, 3, 3, 3

As we can see there are Prime Factors common to both numbers: 2, 3, 3

Now we need to multiply them to find GCF: 2 × 3 × 3 = 18

See Also

About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest common Divisor of 18 and 108? (The answer is: 18). Select the first number (e.g. '18') and the second number (e.g. '108'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder

GCF Table

Number 1Number 2GCF
31083
41084
51081
61086
71081
81084
91089
101082
111081
1210812
131081
141082
151083
161084
171081
18108
191081
201084
211083
221082
231081
24108
251081
261082
2710827
281084
291081
301086
311081
321084

FAQ

What is the Greatest common Divisor of 18 and 108?

GCF of 18 and 108 is 18