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LCM & HCF Calculator

Greatest common divisor and least common multiple.

GCD / HCF (3 numbers)
6
LCM
72
How
Numbers: 12, 18, 24
GCD (greatest common divisor) = 6
LCM (least common multiple)   = 72
Check: GCD ร— LCM = product of pairs (for two numbers)

Fractions: simplify with GCD; add fractions by converting to the LCM denominator. Exact BigInt math.

About the LCM & HCF Calculator

Enter two or more integers and get their greatest common divisor (HCF) and least common multiple at once, computed with the Euclidean algorithm on exact BigInt values. More than two numbers are handled by folding pairwise, and the output echoes your parsed inputs for verification.

How to use the LCM & HCF Calculator

  1. Type at least two integers, separated by commas or spaces.
  2. Read the GCD / HCF and LCM tiles.
  3. Add more numbers to the list to recompute across the whole set.
  4. Open the How box to see the parsed numbers and both results written out.

LCM & HCF Calculator FAQ

How many numbers can I enter?

Any count of two or more โ€” the algorithm folds each new number into the running GCD and LCM, so ten integers work the same as two.

What are GCD and LCM useful for?

Simplifying fractions uses the GCD, adding fractions uses the LCM as a common denominator, and both appear in modular arithmetic and scheduling problems.

Do negatives or decimals work?

Negatives are fine since absolute values are used; non-integer decimals are ignored, and fewer than two valid integers produces a prompt to enter more.