Random Number Generator
What Is Random Number Generation?
Random number generation (RNG) is the process of producing a sequence of numbers that lack any predictable pattern. Computers typically generate pseudo-random numbers using deterministic algorithms, but this tool uses the Web Crypto API (crypto.getRandomValues), which provides cryptographically secure random numbers sourced from the operating system's entropy pool. This means the generated numbers are truly unpredictable and suitable for security-sensitive applications, not just casual use.
How to Use
Set the minimum and maximum values, choose how many numbers to generate, and click Generate. Enable 'Integers only' for whole numbers or disable it for decimals. Use 'Allow duplicates' to control whether the same number can appear more than once.
Cryptographic Randomness
This tool uses crypto.getRandomValues() for cryptographically secure random number generation. The results are truly unpredictable and suitable for any application requiring high-quality randomness.
Common Use Cases
- Games and raffles — draw random winners or generate game elements
- Statistical sampling — select random samples from a population
- Software testing — generate random test data and edge cases
- Education — demonstrate probability concepts and distributions
- Decision making — choose randomly when no preference exists
Tips
When generating unique numbers (no duplicates), make sure the range is large enough to accommodate the requested count. For example, generating 10 unique integers between 1 and 5 is impossible. For lottery-style draws, disable duplicates and set the range to match the lottery's number pool. If you need decimal numbers with specific precision, you can generate integers in a larger range and divide by the desired factor.
Privacy
All processing happens in your browser. No data is sent to any server.
FAQ
How is this tool's randomness different from the usual Math.random?
Math.random produces pseudo-random numbers from a deterministic algorithm, whereas this tool uses the Web Crypto API (crypto.getRandomValues) to draw cryptographically secure numbers from the OS entropy pool. The results are truly unpredictable and suitable even for security-sensitive uses.
Are the generated numbers recorded on a server?
No. Generation happens entirely in your browser, and the results and settings are never sent to, stored on, or logged by a server.
How many numbers can I generate at once, and does it support integers and decimals?
You can set a count to generate several numbers at once. Enable 'Integers only' for whole numbers, or disable it to include decimals, and set any range with the minimum and maximum values.
What should I watch out for when generating without duplicates?
Without duplicates, the range must be wider than the count. For example, you cannot produce 10 unique integers between 1 and 5; in that case the tool shows the error "Range too small for unique count."
How do I set it up for a raffle or lottery draw?
Set the number pool as the minimum and maximum, turn off 'Allow duplicates,' and set the count to the number of winners — you get winning numbers with no repeats. Because each number is equally likely, the draw is fair.