LCM Calculator

Find the Least Common Multiple of two or more numbers quickly.

GCF & LCM Calculator

GCF / HCF / GCD

6

Greatest Common Factor

LCM

72

Least Common Multiple

GCF × LCM = 6 × 72 = 432

LCM Calculator Formula & How It Works

LCM(a,b) = |a × b| / GCF(a,b)
  • LCM = smallest positive integer divisible by all given numbers
  • LCM(a,b) = (a × b) ÷ GCF(a,b)
  • Multiple numbers: LCM(a,b,c) = LCM(LCM(a,b), c)
  • Alternative: prime factorization — take highest power of each prime

The LCM of two numbers is the smallest positive integer divisible by both. LCM(4,6) = 12 because 12 is the smallest number divisible by both 4 and 6. Use LCM to find common denominators when adding or subtracting fractions. LCM(a,b) × GCF(a,b) = a × b — a useful identity.

LCM Calculator FAQs

How is LCM used to add fractions?

To add 1/4 + 1/6: find LCM(4,6)=12. Convert: 3/12 + 2/12 = 5/12. The LCM becomes the common denominator. Always find LCM, not just any common multiple, for the simplest calculation.

What is the difference between LCM and GCF?

GCF (Greatest Common Factor) is the largest divisor shared by numbers. LCM (Least Common Multiple) is the smallest multiple shared by numbers. GCF(12,8)=4, LCM(12,8)=24. Note: GCF × LCM = product of the two numbers (24×4 = 12×8 = 96).

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