Prime Factorization
Break any integer down into its prime factors instantly. Free, private, and calculated right in your browser.
Type in any positive integer and get its full breakdown into prime factors, with repeated primes grouped as exponents (like 360 = 2^3 × 3^2 × 5), handy for simplifying fractions, checking GCD/LCM by hand, or just settling a homework argument about whether a number is prime.
How to use it
- Enter a positive integer
- Hit factor to run the calculation
- Read off the prime factors and exponents
Frequently asked questions
- How do you factor a really big number?
- Trial division gets slow past a few million digits, so the tool switches to Pollard's rho for large factors before falling back to a final primality check. You'll still get an answer for numbers with dozens of digits in a reasonable time.
- How can I tell the result is fully factored, not just divided once?
- Each factor shown has already been tested with a primality check, and repeated factors are grouped with exponents (e.g. 2^4 × 3^2 × 7), so what you see is the complete prime factorization, not a partial split.
- Does it work on numbers that are already prime?
- Yes. If the number itself is prime, the tool just returns that single number as its only factor instead of trying to force a split.
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Nothing is uploaded
The file never leaves your device. There is no server to send it to, so there is nothing to leak, log, or subpoena.
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No signup, no limits
No account, no email, no daily cap, no watermark, and no paid tier waiting behind the third file.
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Works offline
Load the page once and it keeps working with the network off, because all the work was always happening locally.