About GCF Calculator
This GCF calculator finds the greatest common factor of up to ten whole numbers, the largest number that divides all of them, and shows two ways to get it. It is free, needs no sign-up and runs in your browser, so nothing you enter is uploaded.
The page opens on 48 and 180. In prime form they are 2⁴ × 3 and 2² × 3² × 5, so the shared part with the smallest powers is 2^2 × 3 = 12. The Euclidean algorithm gives the same answer in a few divisions.
To simplify a fraction, divide top and bottom by their GCF. For 36/60 the GCF is 12, so the fraction reduces to 3/5.
How to use GCF Calculator
- Choose LCM and GCF, LCM only or GCF only.
- Type two to ten positive whole numbers separated by commas or spaces.
- Read the answer at the top. It updates as you type.
- Check the prime exponent table: the GCF uses the smallest exponents and the LCM the largest.
- Open the steps for the Euclidean algorithm and, for two numbers, the link lcm = a × b ÷ gcd.
Features
- LCM and GCF (GCD, HCF) of 2 to 10 numbers at once.
- Prime factorization method with an exponent table.
- Euclidean algorithm shown division by division.
- Coprime detection.
- Numbers of up to 24 digits, computed exactly with big integers.
- Separate LCM-only and GCF-only views.
- Step list in KaTeX with a copy button for the LaTeX.
GCF
Take only the primes all the numbers share, each to its smallest power.
gcf(48, 180) = 2² × 3 = 12Worked examples
GCF of 48 and 180 gives 12
48 = 12 × 4 and 180 = 12 × 15.
GCF of 36 and 60 gives 12
36 = 12 × 3 and 60 = 12 × 5.
Privacy: how it works
- Everything is calculated by code running in your browser tab. The numbers you enter are not sent to Ulkaa or to any other server, and there is nothing to sign in to.
Tips
- To add fractions, use the LCM of the denominators as the common denominator, which keeps the numbers small.
- To simplify a fraction, divide top and bottom by their GCF in one step.
- If the GCF of two numbers is 1, their LCM is just their product.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial and no credit card. Ulkaa Tool does the work with your own device, so there is no server bill to pass on to you.
Do I need an account?
No. There is no sign-up and no login. Open the page and use it. An Ulkaa account is not needed for anything on this tool.
Does it run in my browser?
Yes. Numbers are processed by code running in your browser tab, on your own device.
Is my data uploaded?
No. Numbers are never sent to Ulkaa or to anyone else. You can check this yourself by watching the Network tab in your browser developer tools while you use the tool.
How do I find the greatest common factor?
List the primes of each number and multiply the primes they share, each to its smallest power. Or use the Euclidean algorithm.
How do I use the GCF to simplify a fraction?
Divide both the numerator and the denominator by the GCF. The result is in lowest terms.
More LCM and GCF Calculator pages
- LCM and GCF CalculatorEnter two to ten whole numbers to get their least common multiple and greatest common factor, with the working.
- LCM CalculatorEnter two to ten numbers to get their least common multiple.
- GCD CalculatorEnter numbers to get the greatest common divisor, with every Euclidean step.
- HCF CalculatorEnter numbers to get their highest common factor, with the working.