Random Number Generator
Generate random numbers with custom ranges
How to use Random Number Generator
Generate random numbers with custom min and max ranges. Single or multiple numbers. Fast, free online random number generator tool.
When do you need a random number?
Random number generation has applications in statistics, gaming, cryptography, education and everyday decision-making. The key is using a generator with sufficient randomness for the intended purpose.
Common uses:
- Prize draws and raffles: Assign each participant a number and use the generator to pick a winner fairly and transparently.
- Statistics and sampling: Researchers use random numbers to select unbiased samples from a population.
- Games and simulations: Dice rolls, card draws, loot drops — any game mechanic requiring chance.
- Education: Teachers generate random student numbers to select who answers a question, ensuring fairness.
- A/B testing: Randomly assign users to test groups to measure the effect of changes without bias.
- Decision-making: Flip a virtual coin or pick a random option when facing equally good choices.
Cryptographic vs. pseudo-random: FlashUtils uses the browser's crypto.getRandomValues() API, which produces cryptographically secure random numbers — suitable even for security-sensitive applications.
Frequently Asked Questions
Are the numbers truly random?
FlashUtils uses the browser's Web Crypto API (crypto.getRandomValues), which generates cryptographically secure random numbers using the operating system's entropy sources (hardware events, timing data). These are suitable even for security applications, unlike simple pseudo-random generators.
Can I generate the same random number twice?
Yes — with a large enough range and enough generations, any number can appear more than once. This is expected behavior. If you need a list of unique numbers (no repeats), generate more than needed and remove duplicates.
What is the difference between random and pseudo-random?
A pseudo-random number generator (PRNG) uses a mathematical formula with a seed — given the same seed, it produces the same sequence. A true random generator uses physical entropy (hardware noise). For most purposes, a cryptographic PRNG like the Web Crypto API is indistinguishable from true randomness.
Can I use random numbers for cryptography?
Yes — if generated with a cryptographically secure generator like the one used here. Never use Math.random() in JavaScript for security purposes — it is a pseudo-random generator not designed for cryptography.
How do I pick a random item from a list?
Assign sequential numbers to each item, generate a random number in that range, and pick the corresponding item. For example, with 10 participants (1-10), generate a number between 1 and 10.
Cryptographic random vs Math.random() vs dice
crypto.getRandomValues() (used here) is cryptographically secure — suitable for tokens, passwords and security applications. Math.random() in JavaScript is a pseudo-random generator — fast but predictable if the seed is known; never use it for security. Physical dice produce true randomness but are impractical for large ranges or bulk generation. Atmospheric noise generators (like random.org) use real-world entropy — marginally more random but require an internet connection and API access.