Prime Number Checker
Check if a number is prime, see its prime factorization and the next prime number. Free online prime checker.
✓ 100% free ✓ No sign up ✓ Runs in your browser — nothing uploaded
Is it prime?
Yes ✓ 97 is prime
Prime factors 97
Next prime 101
How to use Prime Number Checker
- 1Enter your numbers or dates.
- 2Results update instantly as you type.
- 3Copy the main result with one click.
Questions
Is Prime Number Checker free?
Yes. Prime Number Checker is 100% free with no limits, no watermark, no sign up and no email required.
Is my data sent anywhere?
No. Everything is calculated locally in your browser. Nothing you type is sent to or stored on any server.
Does Prime Number Checker work on my phone?
Yes. Prime Number Checker works in any modern browser on iPhone, Android, Windows, Mac, Linux and Chromebook. No app or install needed.
Do I need to create an account?
Never. There is no sign up, no login, no email and no paywall. Just open the page and use it.
How accurate is it?
Calculations use standard formulas with full floating-point precision. For medical, legal or financial decisions, please confirm with a professional.