LCM Calculator
Find the Least Common Multiple (LCM) of 2–10 numbers using prime factorization and GCF methods.
Numbers
Updates as you typeQuick examples (click to load)
Numbers to combine
?
1
2
Paste a list of numbers
Separate numbers with commas, spaces, or new lines. We’ll keep the first 10 valid positive integers.
Method 1 — Prime factorization
Highest power of each prime wins| Number | Enter numbers to see the prime breakdown. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Read each column top to bottom: the bold cell is the highest exponent — that prime power lands in the LCM.
Method 2 — Pairwise GCF
LCM(a, b) = (a × b) ÷ GCF(a, b)- Enter numbers to see the prime breakdown.
Formula
LCM(a, b)
=
|a × b|
GCF (HCF)(a, b)
- LCM
- LCM — Least common multiple — the smallest positive integer divisible by all inputs.
- GCF (HCF)
- GCF — Greatest common factor (also called HCF, GCD) — the largest integer that divides every input.
- Coprime
- Coprime — Two numbers whose GCF is 1; their LCM is simply their product.
WORKED EXAMPLE — YOUR NUMBERS
- Inputs: —
- Prime factorizations: —
- Take highest power of each prime: —
- LCM = —
For more than two numbers, apply the formula pairwise: LCM(a, b, c) = LCM(LCM(a, b), c). Prime factorization scales to any count in one pass — that is why the table view above is usually faster to read for 3+ inputs.