GCF and LCM Calculator


The GCF and LCM calculator (also called the GCF finder) will determine the greatest common factor and least common multiple of a set of two to six numbers. You can also compute the GCF and LCM by hand or use the GCF calculator or LCM calculator

If you want to find the GCF and LCM, first you need to get the prime factorization of each number in the set. This is done easily with the prime factorization calculator.

How to Use the GCF Finder

Suppose you want to find the GCF and LCM of 24 and 56.

  • First we get the prime factorizations of 24 = 2 * 2 * 2 * 3 and 56 = 2 * 2 * 2 * 7.
  • The greatest common factor is what is present in both sets of factors, which is 2 * 2 * 2 = 8.
  • The least common multiple is the highest power of all exponents, which is 2 * 2 * 2 * 3 * 7 = 168.

The factor calculator is also a handy tool in this process. Note that while finding the GCF and LCM of smaller numbers is relatively simple by hand, the GCF and LCM calculator is quicker and much easier for larger numbers or larger set of numbers.