Least Common Multiple Calculator

Find the least common multiple (LCM) of two or more numbers quickly and easily. Enter up to 10 numbers and get the LCM with step-by-step calculations and prime factorization.

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Quick Examples:

Methods to Find LCM

1. Prime Factorization Method

Find the prime factorization of each number, then take the highest power of each prime factor.

Example: LCM(12, 18)
12 = 2² × 3¹
18 = 2¹ × 3²
LCM = 2² × 3² = 4 × 9 = 36

2. Division Method

Divide the numbers by their common factors until no common factors remain, then multiply all divisors and remaining numbers.

Example: LCM(12, 18)
2 | 12, 18 → 6, 9
3 | 6, 9 → 2, 3
LCM = 2 × 3 × 2 × 3 = 36

3. Listing Multiples Method

List the multiples of each number and find the smallest common multiple.

Example: LCM(12, 18)
Multiples of 12: 12, 24, 36, 48, 60...
Multiples of 18: 18, 36, 54, 72...
First common multiple: 36

How to Use This Calculator

1
Enter Numbers
Input at least two positive integers. You can add up to 10 numbers for calculation.
2
View Results
The LCM will be calculated automatically along with additional information like GCD and prime factorization.
3
Study the Steps
Review the step-by-step calculation to understand how the LCM was found.
4
Try Examples
Use the quick example buttons to see how LCM works with different types of numbers.

Applications of LCM

Real-World Applications

  • Scheduling recurring events
  • Finding common denominators in fractions
  • Synchronizing periodic processes
  • Planning production cycles
  • Calculating gear ratios
  • Determining meeting frequencies

Mathematical Applications

  • Adding and subtracting fractions
  • Solving Diophantine equations
  • Number theory problems
  • Modular arithmetic
  • Cryptography algorithms
  • Computer science algorithms

Example Calculations

Example 1: Two Numbers

Find LCM(24, 36):

24 = 2³ × 3¹
36 = 2² × 3²
LCM = 2³ × 3² = 8 × 9 = 72

Example 2: Three Numbers

Find LCM(12, 15, 20):

12 = 2² × 3¹
15 = 3¹ × 5¹
20 = 2² × 5¹
LCM = 2² × 3¹ × 5¹ = 4 × 3 × 5 = 60

Example 3: Prime Numbers

Find LCM(7, 11, 13):

7, 11, and 13 are all prime numbers
LCM = 7 × 11 × 13 = 1001
Note: LCM of prime numbers is their product

Frequently Asked Questions

What is the difference between LCM and GCD?

LCM (Least Common Multiple) is the smallest positive number that is divisible by all given numbers, while GCD (Greatest Common Divisor) is the largest number that divides all given numbers.

Can LCM be smaller than the largest input number?

No, the LCM is always greater than or equal to the largest input number. It equals the largest number only when that number is divisible by all other input numbers.

What happens with prime numbers?

When finding the LCM of prime numbers, the result is simply their product since prime numbers have no common factors other than 1.