LCM Calculator
Find the least common multiple of two or more whole numbers — the smallest number that every one of them divides into exactly. Enter the numbers separated by commas to get the LCM along with the greatest common factor.
- Greatest common factor
- 2
- LCM ÷ each number
- 15, 10, 6
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Formula
How to use it
- Type two or more positive whole numbers separated by commas or spaces.
- Read the least common multiple.
- The last line shows how many times each number goes into the LCM.
Worked examples
LCM of 4, 6 and 10
- Least common multiple
- 60
- Greatest common factor
- 2
- LCM ÷ each number
- 15, 10, 6
LCM of 8 and 12
- Least common multiple
- 24
- Greatest common factor
- 4
- LCM ÷ each number
- 3, 2
Working it out by hand
For 4, 6 and 10: LCM(4, 6) = 4 × 6 ÷ 2 = 12, then LCM(12, 10) = 12 × 10 ÷ 2 = 60.
Or use prime factors: 4 = 2², 6 = 2 × 3, 10 = 2 × 5. Take the highest power of every prime that appears: 2² × 3 × 5 = 60.
Where the LCM shows up
Adding fractions: the LCM of the denominators is the least common denominator. Repeating events: buses that leave every 8 and every 12 minutes depart together every 24 minutes. Packaging: hot dogs in packs of 10 and buns in packs of 8 come out even at 40.
Questions people ask
What is the LCM of 4 and 6?
12. The multiples of 4 are 4, 8, 12… and the multiples of 6 are 6, 12…; 12 is the first they share.
What is the LCM of 8 and 12?
24.
What is the LCM of 4, 6 and 10?
60.
What is the difference between LCM and GCF?
The GCF is the largest number that divides into all your numbers; the LCM is the smallest number that all your numbers divide into. For 8 and 12 the GCF is 4 and the LCM is 24.