LCM Calculator
Find the least common multiple of two or more numbers. The calculator factorises each number into primes and builds the LCM from the highest power of every prime, showing the working so the method is clear.
How to Use
Type your numbers separated by commas, spaces or new lines. The least common multiple is the smallest number that every input divides into exactly, and it is also the number you use as a common denominator when adding fractions.
- Two or more numbers at once
- Prime factorisation of each input
- Shows how the LCM is assembled
- Greatest common divisor reported alongside
- Multiples list for verification
The method
Every whole number greater than one has a unique prime factorisation. The LCM takes the highest power of each prime found across all the inputs, while the GCD takes the lowest. That is why LCM(a, b) × GCD(a, b) always equals a × b.
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