GCF and LCM Calculator
Greatest common factor and least common multiple, with prime factors.
Enter your values
Enter the numbers (comma separated) you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Greatest common factor
- 12
- Least common multiple
- 360
- Product of all numbers
- 51,840
| Number | Prime factorisation |
|---|---|
| 24 | 2 × 2 × 2 × 3 |
| 36 | 2 × 2 × 3 × 3 |
| 60 | 2 × 2 × 3 × 5 |
Quick answer
The GCF is the largest number dividing all inputs; the LCM is the smallest number all inputs divide into.
LCM(a,b) = a × b ÷ GCF(a,b)
At a glance
| What it does | Greatest common factor and least common multiple, with prime factors. |
|---|---|
| Category | Math |
| Inputs needed | Numbers (comma separated) |
| Main output | Greatest common factor |
| Formula | LCM(a,b) = a × b ÷ GCF(a,b) |
| Cost | Free — no sign-up, no download |
How to use the GCF and LCM Calculator
- 1Type your numbers separated by commas.
- 2Read the GCF and LCM.
- 3Check the prime factorisation table for the working.
Inputs explained
- Numbers (comma separated)
- Enter the numbers (comma separated) you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Numbers (comma separated)24, 36, 60
Results
- Greatest common factor12
- Least common multiple360
- Product of all numbers51,840
Frequently asked questions
When do I need the LCM?
Adding fractions with different denominators, and scheduling problems where two cycles must line up.
What if the GCF is 1?
The numbers are coprime — they share no common factor, and their LCM is simply their product.
What do I need to enter into the GCF and LCM Calculator?
Just 1 value: numbers (comma separated). Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the GCF and LCM Calculator work out the answer?
The GCF is the largest number dividing all inputs; the LCM is the smallest number all inputs divide into. It applies the formula LCM(a,b) = a × b ÷ GCF(a,b) and shows the working so you can check each step by hand.
Is the GCF and LCM Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.