GCD & LCM Calculator

Our GCD & LCM Calculator allows you to find the greatest common divisor and least common multiple of two or more numbers quickly and accurately. Enter your numbers to calculate GCD, LCM, and understand the relationship between them. Ideal for students, teachers, and anyone solving math problems related to divisibility.

Enter 2 or more positive integers separated by commas

FAQ – GCD & LCM Calculator

What is a GCD & LCM Calculator?

A GCD & LCM Calculator helps you find the Greatest Common Divisor (GCD) and the Least Common Multiple (LCM) of two or more numbers. It’s useful in simplifying fractions, solving math problems, and understanding number relationships.

What is GCD (Greatest Common Divisor)?

The GCD, also known as the HCF (Highest Common Factor), is the largest number that divides two or more numbers without leaving a remainder.
Example: GCD of 12 and 18 is 6.

What is LCM (Least Common Multiple)?

The LCM is the smallest positive number that is a multiple of two or more numbers.
Example: LCM of 4 and 5 is 20.

How do you calculate GCD and LCM?

You can find the GCD using:

  • Prime factorization
  • Euclidean algorithm (dividing and finding remainders)

Once you know the GCD, you can find the LCM using this formula:

LCM(a, b) × GCD(a, b) = a × b
Can the calculator find GCD and LCM of more than two numbers?

Yes, most advanced calculators can find GCD and LCM for two or more numbers at once. Just enter the numbers separated by commas.

Why are GCD and LCM important?

They are widely used in:

  • Simplifying fractions
  • Solving algebraic equations
  • Finding repeating cycles in math or time problems
  • Determining ratios and proportions
What if one of the numbers is zero?

GCD(0, n) is n (because any number divides 0).
LCM(0, n) is 0 (because 0 has no multiples).

Can I use decimals or negative numbers?

No, GCD and LCM are defined only for positive integers. You can convert decimals to integers before calculating.

Is the GCD always smaller than the LCM?

Yes, except when both numbers are equal, where GCD = LCM = the number itself.