What is Prime Checker?

Test if a number is prime and get its prime factorization.

Is Prime Checker free to use?

Yes — Prime Checker is free to use, with no sign-up, no install and no account.

No — Prime Checker runs entirely in your browser, so your text, files and results never leave your device.

No — it works in any modern browser (Chrome, Edge, Firefox, Safari) with no downloads, accounts or plugins.

What is Prime Checker?: Test if a number is prime and get its prime factorization.
Is Prime Checker free to use?: Yes — Prime Checker is free to use, with no sign-up, no install and no account.
Does Prime Checker upload or store my data?: No — Prime Checker runs entirely in your browser, so your text, files and results never leave your device.
Do I need to install anything to use Prime Checker?: No — it works in any modern browser (Chrome, Edge, Firefox, Safari) with no downloads, accounts or plugins.