SCHOOL PLANNING AND CORE MATH
GCF and LCM Calculator
Find the greatest common factor and least common multiple of two whole numbers.
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Enter your values and select Calculate. Your result stays on this device.
How it works
GCF is found with the Euclidean algorithm. LCM = |first × second| ÷ GCF when both numbers are nonzero.
Assumptions
Inputs are converted to nonnegative whole numbers.
About this calculator
This GCF and LCM calculator keeps two related classroom operations together. It uses whole numbers and shows both answers so factor checks and common-denominator work are easier to verify.
How to use it
- Enter two nonnegative whole numbers.
- Review the greatest common factor.
- Use the least common multiple for shared-cycle or denominator problems.
- Check the original problem to decide which result is relevant.
Use case
GCF and LCM calculator: a clear planning check
Enter two whole numbers to see both GCF and LCM together, with the Euclidean method and the relationship between factors and multiples kept visible.
Find and compare the greatest common factor and least common multiple of two whole numbers for a school-math task.
Source and update
Last reviewed: 2026-08-10
NIST — International System of Units guidanceFrequently asked questions
What is the GCF?
The greatest common factor is the largest whole number that divides both entered numbers without a remainder.
What is the LCM?
The least common multiple is the smallest nonnegative multiple shared by both numbers.
Can I enter decimals?
This tool is for whole-number factor and multiple problems; decimal inputs are converted to whole numbers.
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