Greatest Common Factor Calculator
The greatest common factor, or GCF, is the biggest whole number that divides evenly into two numbers. It is useful for simplifying fractions and splitting things into equal groups.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
List the factors of each number, then pick the largest one they share. A quicker route uses repeated division, which the calculator handles for you.
Once you know the GCF, dividing both numbers by it gives the smallest pair of whole numbers with the same ratio.
Worked example
The greatest common factor of 48 and 180 is 12.
Questions
What is a factor?
A factor is a whole number that divides into another number with nothing left over. Three is a factor of twelve, since three times four is twelve.
How do I simplify a fraction with it?
Divide the top and bottom numbers by their greatest common factor. The fraction is then in lowest terms.
What if the two numbers share no factor except one?
Then their greatest common factor is one, and the numbers are called coprime.
More like this
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- Average CalculatorMean of a list of numbers.
- Percent Difference CalculatorGap between two values, as a share of their average.
- Standard Deviation CalculatorSpread of a list of numbers.
- Weighted Average CalculatorAverage where some values count more.