Math

LCM Calculator

Find the least common multiple of two numbers.

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Inputs

Adjust the assumptions to match your scenario. Results update instantly.

Results

Primary outputs and comparison insights are built from the current inputs.

LCM

36

Least common multiple.

GCF

6

Greatest common factor.

LCM/GCF ratio

6

Ratio of LCM to GCF.

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How this calculator works

The LCM Calculator finds the least common multiple of two numbers, useful for adding fractions and scheduling problems. Enter number 1 and number 2 to estimate lcm, gcf, and lcm/gcf ratio. The calculator updates instantly and adds a comparison table plus chart so you can test the sensitivity of the result before you use it in a decision.

Quick guide

Jump straight to the section you need, then return to the calculator.

Inputs

  • First positive integer.
  • Second positive integer.

Outputs

  • Least common multiple.
  • Greatest common factor.
  • Ratio of LCM to GCF.

Assumptions

  • Inputs are positive integers.
  • Uses the GCF-based method for efficiency.

Tips

  • LCM is key for adding fractions with different denominators.
  • For more than 2 numbers, compute LCM iteratively.

Formula guide

Use these formulas to audit the output or explain it to someone else.

1 formulas

LCM = (a × b) ÷ GCF

Usage examples

Review a ready-made scenario, copy it, then tweak inputs to match your case.

Example

2 inputs3 outputs

Scheduling problem

Inputs

  • Example input Number 1: 15
  • Example input Number 2: 20

Outputs

  • Example result LCM: 60
  • Example result GCF: 5
  • Example result LCM/GCF ratio: 12

LCM of 15 and 20 is 60, meaning events on 15-day and 20-day cycles coincide every 60 days.

LCM by second number

5 of 5 rows
Number 2LCMGCF
121212
15603
18366
21843
242412

When two numbers share few factors, the LCM is close to their product.

LCM growth

Highest: 21 (84)Lowest: 12 (12)
Number 2LCM

Focus point

12

12

Position

#1 of 5

Original order

Share of total

5.56%

Total: 216

PositiveNegative

When two numbers share few factors, the LCM is close to their product.

References

  • LCM calculation methods
  • Applications in arithmetic

FAQ

Common questions

What does the LCM Calculator do?

The LCM Calculator finds the least common multiple of two numbers, useful for adding fractions and scheduling problems. Enter number 1 and number 2 to estimate lcm, gcf, and lcm/gcf ratio. The calculator updates instantly and adds a comparison table plus chart so you can test the sensitivity of the result before you use it in a decision. It is part of our math toolkit.

What inputs do I need?

Typical inputs include First positive integer., Second positive integer..

How are the results calculated?

We follow the formulas and assumptions outlined in the "How this calculator works" section. You will see outputs like Least common multiple., Greatest common factor., Ratio of LCM to GCF..

Can I share or download the results?

Use the Copy link or Print buttons to share your results. If a table or chart appears, you can download the data as CSV.

Is my data stored?

No. Calculations run in your browser and we do not store your inputs.