Home›Math Tools›Random Number Generator
Random Tools

Random Number Generator — Min, Max & Unique

Generate one or many random whole numbers within a range you choose, with an optional setting to guarantee no repeated values.

Advertisement

🎲 Set Your Range

🎲 Result

Set your range and count, then generate to see your random numbers
⚠️

Disclaimer: This tool is intended for general, educational, and casual use (games, raffles, sampling, etc). It is not certified for regulated gambling, lotteries, or cryptographic key generation.

How This Random Number Generator Works

This tool produces whole numbers uniformly distributed across the range you set, meaning every value between your minimum and maximum (inclusive of both endpoints) has an equal chance of appearing. Behind the scenes, it prefers your browser's crypto.getRandomValues function when available, which draws from your operating system's secure random number source. If that API isn't supported, it automatically falls back to JavaScript's built-in Math.random() so the generator still works.

Unique Values Mode

When you check "unique values only," the generator builds the full list of every possible integer in your range, shuffles that list thoroughly (using a well-known technique called a Fisher-Yates shuffle), and then hands you the first however-many numbers you asked for. This guarantees no duplicates while keeping every possible ordering equally likely. If you ask for more unique numbers than actually exist in your range — for instance, 20 unique numbers between 1 and 10 — the tool tells you that's not possible rather than guessing.

Worked Example

Say you want 5 unique numbers between 1 and 10. The generator lists out [1,2,3,4,5,6,7,8,9,10], shuffles that list randomly, and returns the first 5 entries — for example, 7, 2, 10, 4, 9. Every one of the 10 numbers had an equal chance of landing in any position, and none can repeat because each was only in the list once to begin with.

Frequently Asked Questions

Yes. Both endpoints are inclusive — if you set min to 1 and max to 6 to simulate a die roll, both 1 and 6 are valid outcomes, just like every value in between.
The tool shows a message instead of a result. For example, a range of 1 to 10 only contains 10 possible integers, so requesting 15 unique values is mathematically impossible — you'd need to widen the range or lower the count.
When it's available in your browser, crypto.getRandomValues draws from the operating system's cryptographically secure random source, which tends to have better statistical uniformity than Math.random's pseudo-random generator. This tool uses it automatically when supported, and quietly falls back to Math.random otherwise so the generator still works everywhere.
Advertisement