Calculate GCD & LCM

Find the greatest common divisor and least common multiple of integer inputs.

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ToolGCD & LCM Calculator
Input
Output
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How it works

The Euclidean algorithm repeatedly replaces a pair with divisor and remainder until the remainder is zero; the final absolute divisor is the GCD. The LCM is absolute product divided by GCD, extended across the list.

  • At least two integers are required.
  • Decimal-looking input is rounded before calculation.

Worked example

GCD and LCM of Two Numbers
Find GCD and LCM of 12 and 18
Input
											12, 18
Output
												GCD(12, 18) = 6
LCM(12, 18) = 36

When to use this

Schedules find shared cycles, fraction reducers find common divisors, and number-theory lessons compare GCD with LCM.

Edge cases

  • An all-zero list has an undefined LCM.
  • Negative numbers are normalized by absolute value.
  • Decimal inputs are rounded rather than treated as exact rationals.