GCF & LCM Calculator

Find the Greatest Common Factor and Least Common Multiple for any set of numbers. Includes prime factorization trees and formula derivation.

Enter at least 2 numbers separated by commas
Greatest Common Factor (GCF)
Least Common Multiple (LCM)

Formula Method

Enter numbers above to see the GCF and LCM formula derivation.

Prime Factorization

About TooliFyra GCF & LCM Calculator Online

Our GCF & LCM calculator online finds the Greatest Common Factor and Least Common Multiple for any set of numbers. Beyond just giving answers, this GCF & LCM calculator online shows the complete prime factorization tree for each number and explains the mathematical formula used.

The GCF is the largest number that divides all given numbers without leaving a remainder. The LCM is the smallest number that is a multiple of all given numbers — both fundamental concepts in mathematics.

Key Features

Unlimited NumbersEnter any number of values separated by commas.
Prime Factorization TreesSee the complete factor breakdown for each number.
Formula DerivationUnderstand how GCF and LCM are derived mathematically.

How to Use the GCF & LCM Calculator Online

  1. Enter at least 2 numbers separated by commas in the text area.
  2. The GCF and LCM are calculated instantly and displayed in large result cards.
  3. View the prime factorization tree for each number in the grid below.
  4. Read the formula derivation to understand how the results were obtained.

Benefits of Using This GCF & LCM Calculator Online

Students can verify homework and understand the factorization process. Teachers can demonstrate prime factorization and GCF/LCM concepts. Math enthusiasts can explore number properties.

Use Cases

Education: Learn prime factorization and GCF/LCM concepts.
Fractions: Simplify fractions and find common denominators.
Problem Solving: Solve ratio and word problems efficiently.

Why TooliFyra?

TooliFyra's GCF & LCM calculator online is 100% private — all calculations happen in your browser. It's completely free with no sign-up or data collection.

Frequently Asked Questions

The Greatest Common Factor (GCF) is the largest positive integer that divides all given numbers without leaving a remainder. Also known as GCD (Greatest Common Divisor).

The Least Common Multiple (LCM) is the smallest positive integer that is divisible by all given numbers.

Yes, completely free with no usage limits.