GCF & LCM Calculator
greatest common factor & least common multiple
Find the GCF (also called HCF) and LCM of two or more numbers, with the full prime-factorization working shown. Built for TN Board, CBSE and TNPSC students โ free, unlimited, no sign-up needed.
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Common GCF & LCM Pairs (Reference Table)
Free Online GCF (HCF) & LCM Calculator for Indian Students
This free GCF and LCM calculator instantly finds the greatest common factor (also called HCF, the Highest Common Factor) and the least common multiple of two or more whole numbers โ with the full prime-factorization working shown, not just the final answer. It's built for TN Board, CBSE and TNPSC students who need a fast, reliable way to check their working on homework or exam practice.
GCF/HCF and LCM are core to simplifying fractions, adding fractions with different denominators, and solving word problems about repeating events. This tool shows the prime factorization of each number side by side, then explains exactly how the lowest common powers give the GCF and the highest common powers give the LCM โ the same method your textbook expects you to show for full marks.
If you're stuck on why GCF or LCM works, or which one to use in a word problem, StudyHelpAI's free AI Maths tutor explains the concept and the reasoning step by step in English or Tamil.
โ Back to Maths Homework HelpGCF & LCM Calculator โ Questions Answered
Yes โ it's completely free with no sign-up, no daily limit, and no ads. It runs entirely in your browser, so results are instant.
Nothing โ they're the same thing. GCF (Greatest Common Factor) is the term used more in CBSE/international textbooks, while HCF (Highest Common Factor) is the term more common in TN Board textbooks. This calculator gives you both under one label.
Yes โ click "Add another number" to include a third, fourth, or more numbers. The calculator finds the GCF and LCM across all of them at once.
Write out the prime factorization of each number, then take the lowest power of every common prime for the GCF, and the highest power of every prime that appears in any number for the LCM. This calculator shows that exact working below your result.
Yes โ if two numbers share no prime factors (they are "coprime"), the GCF will be 1 and the LCM will simply be the product of the numbers.