GCF Calculator (HCF Calculator)

Enter up to 10 numbers to calculate Greatest Common Factor (GCF / HCF/ GCD) using our GCF/HCF Calculator.

Min required 2 values comma saprated


If the number ‘a’ divided another number ‘b’ exactly, then we say that ‘a’ is a factor of ‘b’.
In this case, ‘b’ is called a multiple of ‘a’.

HCF or Highest Common Factor (a.k.a Greatest common factor) refers to a set of two or more different numbers that can be divided by exactly or a common number. HCF finder is also called as GCD/GCM – Greatest Common Divisor, Greatest common denominator, or Greatest Common Factor.

LCM or Least Common Multiple refers to the smallest quantity of number that is divisible by two or more given quantities of number without a remainder: 12 is the least common multiple of 2, 3, 4, and 6. LCM is also called as Lowest Common Multiple. LCM is the smallest number that is a multiple of two or more numbers.

GCF - Greatest common factor can be calculated by any of the following methods,

HCF Calculator uses the following methods to find the greatest common divisor:

  • List of Factors Method
  • Prime Factorization Method
  • Division Method
  • Euclidean Algorithm
  • Binary (Stein's) Algorithm 
  • Upside Down Division

How to Calculate HCF?

Highest Common Factor or GCF by Factorization Method

HCF Using prime factorization or tree method

In the above picture, the greatest common factor of 12 and 16 is found through the factorization method. Firstly, all the factors of both the numbers are written and the largest number is considered as HCF.

Greatest Common Factor / HCF by Division Method

GCf or HCf using Division Method

This is another method of finding the greatest common factor of 30 and 42. Firstly, you have to divide the largest number by the smallest number in the first step.

In the second step, the divisor will become the new dividend and so in the next steps. Until the remainder becomes zero, continue the steps where the last divisor will be HCF. In the picture above, the last divisor is 6 when the remainder is 0 and this divisor is the Greatest Common Factor.

HCF or GCF by Factor Tree (Prime Factorization)

HCF or GCf using Factor tree method or prime factorization

In simple steps, you can use the Factor Tree method to find the greatest common factor of 24 and 36 as shown in the above picture.

Firstly, make the factors of both the number like it is made for 24 and 36 in the above image. Then find the common factors in both the number, line for 24 and 36, the common factors are 2,2,3.

Later, multiple the common factors to get the GCF, and if there’s only one common factor then no need to multiply.

(Greatest common divisor) Division Method:

You can find the HCF of two given numbers using this GCF calculator, or divide the largest by the small number, then divide the dividend by the remainder. Repeat this until the remainder is 0. The last dividend is the HCF of the two numbers.
Least Common Factor(LCF) can be calculated by the following method,

Factorization Method:

Express each one of the numbers as a product of prime factors.
The product of the highest powers of all prime factors gives LCF.


Calculate the HCF (GCF or GCD) and LCM for the given set of numbers.

Greatest Common Factor of 18,36,72


Step1: Express the numbers as a product of prime factors.
18 = 2× 32
36 = 22 × 32
72 = 23 × 32

Step2: Take the prime numbers with the least power and is present in all sets.
2 and 3 are the prime number common to all given numbers.
The least power of 2 in the set is - 2
The least power of 3 in the set is - 32

Step3: Product of the numbers taken.
32 × 2 = 9 × 2 = 18

So 18 is the GCD (Greatest Common Divisor) of the numbers.

Least Common Multiple or Factor of 36, 90, 72.

Step1: Express the numbers as a product of prime factors.
36 = 22 × 32
90 = 2 × 5 × 32
72 = 23 × 32

Step2: Take the prime numbers with the highest power for all prime numbers.
2, 3,5 are the prime number identified.
The highest power of 2 in the set is - 23
The highest power of 3 in the set is - 32
The highest power of 5 in the set is - 5

Step3: Product of the numbers taken.
32 × 5 × 23 = 9 × 5 × 8 = 360

So 360 is the LCM (Least Common Multiple) of the numbers.

Table of Highest Common Factor.

HCF of 2 and 4 is 2
HCF of 2 and 5 is 1
HCF of 3 and 4 is 1
HCF of 5 and 25 is 5
HCF of 4 and 5 is 1
HCF of 16 and 24 is 8
HCF of 5 and 7 is 1
HCF of 15 and 20 is 20
HCF of 13,23 and 14 is 1
H.C.F of 8,9 and 25 is 1
HCF of 2 and 3 is 1
HCF of 4 and 8 is 4
HCF of 3,4 and 6 is 1
HCF of 3 and 5 is 1
HCF of 680,510 and 340 is 4
HCF of 2 and 8 is 2
HCF of 18 and 48 is 6
HCF of 12 and 48 is 12
HCF of 30 and 42 is 6


  1. Stapel, E., 2020. LCM And GCF | Purplemath.
  2. 2020.
  3. 2020. Find Greatest Common Factor (GCF) In Maths.
  4. Estela, M., 2020. Finding Greatest Common Factor Using The List Method - Chilimath.
  5. Math Only Math. 2020. Highest Common Factor Of Monomials | Greatest Common Factor Monomials.