How to use the LCM and HCF Calculator
- 1. Enter your numbersType two or more whole numbers, split by commas or spaces.
- 2. Press the buttonThe tool finds the LCM and HCF together.
- 3. Read the factorsSee each number's prime factors in a table.
What LCM and HCF mean
The HCF, or highest common factor, is the largest number that divides all your numbers. It is also called the GCD. The LCM, or lowest common multiple, is the smallest number that all your numbers divide into.
For two numbers, there is a neat link: LCM × HCF = the product of the two numbers.
Worked example with prime factors
Take 12, 18 and 24.
- 12 = 2^2 × 3
- 18 = 2 × 3^2
- 24 = 2^3 × 3
For the HCF, take the lowest power of each prime found in all the numbers. That gives 2 × 3 = 6.
For the LCM, take the highest power of each prime. That gives 2^3 × 3^2 = 72.
The result table shows these factors for your own numbers, so you can copy the working into your notebook.
Where you use these
LCM helps you find a common denominator when adding fractions. It also answers timing questions, such as when two buses leaving at different intervals will next meet. HCF helps you simplify fractions and split things into equal groups.
The tool accepts whole numbers above 0. Each number can go up to one lakh crore, and the LCM stays exact even when it is very long.
Next, try the fraction calculator, which simplifies for you, or the average calculator.
Frequently asked questions
Is HCF the same as GCD?
Yes. Highest common factor and greatest common divisor mean the same thing.
Can I find the LCM of more than two numbers?
Yes. Enter up to 50 whole numbers.
Does it work with decimals or negative numbers?
No. LCM and HCF here are for whole numbers above 0.
Is this tool free?
Yes. It asks for your name and WhatsApp number once, at result time, and other Uncodemy tools then open without the form.