About Factor Calculator
Factor Calculator is a free set of math tools for working with factors, prime factorization, and divisors. Every calculator shows the full working, not just the answer — the goal is that you leave understanding the method, not only the result.
What this site does
The site covers the core operations students meet when learning about factors and divisibility:
- Factor Calculator — every factor of a number, with factor pairs and a factor tree
- Prime Factorization — break a number into primes with step-by-step division
- GCF Calculator — greatest common factor via three methods
- LCM Calculator — least common multiple with worked steps
- Common Factors — every shared factor, not just the largest
- Divisor Calculator — divisor count, divisor sum, and number classification
There are also individual reference pages for every number from 1 to 1200 — for example factors of 12 or factors of 100. You can browse them all on the sitemap.
How the calculations work
All calculations run directly in your browser using standard number theory algorithms — trial division up to the square root for factors, the Euclidean algorithm for GCF, and the divisor function formulas for counts and sums. Nothing is sent to a server, and no data about your inputs is stored.
The results are verified against established mathematical references, including the On-Line Encyclopedia of Integer Sequences (OEIS) for divisor counts and divisor sums.
Who built this
Factor Calculator is built and maintained by Naveed Nazeer, a web developer working on educational tools. If you spot an error, have a suggestion, or want a calculator added, the contact page is the fastest way to reach me.
Accuracy and corrections
Mathematical accuracy is the priority here. Every calculator is covered by automated tests that check results against known values before any change goes live. If you do find something wrong, please report it — corrections are made quickly and the fix applies across every page that uses the same calculation.
Cost
Everything on this site is free to use, with no sign-up, no usage limits, and no paywalled features.