Prime Number Generator — Free, No Upload, Browser-Based

Generate every prime number within any range up to one million using the Sieve of Eratosthenes — the fastest classical algorithm for the job. Set a lower and upper bound, and results appear instantly without sending anything to a server. Your input never leaves the browser, making this a safe choice for offline use and privacy-conscious environments.

How to use this tool

1. Enter a lower bound (From) and upper bound (To), or pick a preset range.
2. The sieve runs instantly and lists every prime in the range.
3. Click "Copy all" to copy the comma-separated list to your clipboard.