About HCF Calculator
This HCF calculator finds the highest common factor, the same thing as the GCF or GCD, for up to ten whole numbers, with the prime factor and division methods. It is free, needs no sign-up and runs in your browser, so nothing you enter is uploaded.
The page opens on 126, 198 and 270. Their prime factorizations are 2 × 3² × 7, 2 × 3² × 11 and 2 × 3³ × 5. The shared primes with the smallest powers are 2 × 3² = 2 × 3^2, so the HCF is 18.
HCF is the term used in British, Indian and many other exam systems, with the common-division ladder as the usual school method. The LCM, which exam questions often ask for alongside, is shown too.
How to use HCF 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.
HCF
The HCF is the product of the common prime factors to their lowest powers.
HCF(126, 198, 270) = 2 × 3² = 18Worked examples
HCF of 126, 198 and 270 gives 18
LCM of the same numbers is 20790.
HCF and LCM of 12 and 18 gives HCF 6, LCM 36
HCF × LCM = 6 × 36 = 216 = 12 × 18.
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.
Is HCF the same as GCF?
Yes. HCF, GCF and GCD are three names for the greatest number that divides all the given numbers.
How are HCF and LCM related?
For two numbers, HCF × LCM = the product of the numbers.
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.
- GCF CalculatorEnter two to ten numbers to get their greatest common factor.
- GCD CalculatorEnter numbers to get the greatest common divisor, with every Euclidean step.