## Free GCD and LCM Calculator

### Free Online Math Calculators

Quickly determine:
• Greatest Common Divisor - GCD, aka
Greatest Common Denominator - GCD, aka
Greatest Common Factor - GCF, or finally
Highest Common Factor - HCF and
• Least Common Multiple - LCM, aka
Lowest Common Multiple - LCM, or
Smallest Common Multiple - SCM
Lowest Common Denominator - LCD
between two or three numbers.

You shouldn't mix up those two. If you need a little reminding, scroll below this free calculator to refresh your memory.

First Number: Second Number:
Third Number (not required):

Greatest Common Factor (GCF):
Least Common Multiplier (LCM):

Free JavaScripts provided
by
The JavaScript Source

Little intro:

 2 × 3 = 6 factor × factor = multiple (product)

And now the examples of both.

LCD/LCM story: (LCD is not a computer monitor here) ;-)

"Least common denominator of 2 or more whole numbers (integers) is the smallest positive whole number that is a multiple of those numbers."

Here's one application of LCD/LCM. When you're adding or subtracting fractions you must make your denominators the same.

 2 + 1 = 2×2 + 1×3 = 4 + 3 = 4 + 3 = 7 3 2 3×2 2×3 6 6 6 6
=> that's when you do go for LCD/LCM, and in this case your LCD = 6

GCF/GCD story:

"Greatest common factor of 2 or more non-zero whole numbers (integers), is the biggest positive number that divides those numbers without a remainder."

And when you're trying to put something in front of parentheses, say:

6a + 3b = 3×(2a + b)

=> that's when you do go for GCF (Greatest Common Factor), and in this case your GCF = 3