GCF and LCM Calculator — Two Integers | How to use and interpret results
Find a greatest common factor for simplifying fractions and a least common multiple for shared repetition intervals. Integer arithmetic preserves the final digits of large results.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
How to use this tool
Enter integers from 1 through 1 trillion in both fields. Empty input, zero, negative numbers, fractions and out-of-range values are rejected.
Results and examples
For 12 and 18, GCF is 6 and LCM is 36. For 1 trillion and 999,999,999,999, the LCM is exactly 999,999,999,999,000,000,000,000 rather than a rounded floating-point approximation.
Worked example
For 12 and 18, GCF is 6 and LCM is 36. For 1 trillion and 999,999,999,999, the LCM is exactly 999,999,999,999,000,000,000,000 rather than a rounded floating-point approximation.
Limitations
- Only two integer values are accepted; polynomials and fractions are outside the input model.
- Prime-factor trees and worked factorisation steps are not printed.
Fields
| Field | Guidance and constraints |
|---|---|
| First number | Accepted range: 1–1000000000000 · Input step: 1 |
| Second number | Accepted range: 1–1000000000000 · Input step: 1 |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
What happens to 12.5?
It is rejected as invalid input rather than truncated to 12.
Are GCF and GCD different here?
No. Both refer to the greatest common divisor of the two integers.
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