Question 1

Is this random number generator truly random?

Accepted Answer

Yes — this generator uses crypto.getRandomValues(), a cryptographically secure pseudo-random number generator (CSPRNG) built into every modern browser. Unlike Math.random(), which relies on a deterministic algorithm seeded by the system clock and can be predicted under certain conditions, crypto.getRandomValues() draws entropy directly from the operating system. The same API is used to generate TLS session keys and cryptographic tokens, making it the gold standard for unpredictability in web applications.

Question 2

What is the maximum number size I can generate?

Accepted Answer

In Basic mode, Min and Max are capped at ±1,000,000 for fast standard integer arithmetic. In Comprehensive mode, you can enter integers with up to 999 digits — vastly exceeding JavaScript's native safe integer limit of 2⁵³ − 1. This is possible because the Comprehensive tab uses JavaScript's BigInt type with a rejection-sampling algorithm: it generates random bytes, converts them to a BigInt, discards any value outside the target range, and retries until a valid result is found.

Question 3

Can I generate decimal numbers?

Accepted Answer

Yes — switch to the Comprehensive tab, set the type to Decimal, and choose between 1 and 999 decimal places. Internally, the tool avoids floating-point rounding errors by scaling the range to integers using BigInt arithmetic, performing the random selection at integer precision, and then inserting the decimal point into the result string at the correct position. This guarantees exact decimal output regardless of how many decimal places you request.

Question 4

Can I generate numbers without repeats?

Accepted Answer

Yes — in List mode, toggle the No Duplicates option. The generator tracks previously produced values in a JavaScript Set and retries whenever a duplicate would be added, continuing until the requested count of unique values is reached. This works as long as the range size (Max − Min + 1) is at least as large as the count you requested. If the range is too small, the tool displays a clear error message rather than looping indefinitely.

Question 5

Can I use this for a lottery or raffle?

Accepted Answer

Yes, this tool is well-suited for lotteries and raffles. Enable No Duplicates in List mode and set Min and Max to match your lottery pool — for example, 1 to 49 for a standard draw. Each number is generated using crypto.getRandomValues(), a cryptographically secure source, so results are statistically independent and cannot be predicted or manipulated. The absence of server involvement also means no third party can influence or observe the draw.

Question 6

Does the tool store or send my numbers anywhere?

Accepted Answer

No — all generation runs entirely inside your browser using JavaScript. When you click Generate, the page calls crypto.getRandomValues() locally, builds the result list, and displays it on screen with no outgoing network request. You can verify this in your browser's developer tools: open the Network tab and watch for activity while generating — no requests related to number generation will appear. Refreshing the page clears all results.

Question 7

What is the difference between crypto.getRandomValues() and Math.random()?

Accepted Answer

Math.random() uses a deterministic algorithm — typically xorshift128+ or a similar PRNG — seeded from the system clock at startup. Given the seed or sufficient output samples, its future values can be predicted. crypto.getRandomValues() reads from the operating system's entropy pool, which accumulates randomness from hardware events like keyboard timing, disk I/O, and network interrupts. This makes it suitable for security applications where predictability is a vulnerability — the two functions are not interchangeable in any context where fairness or security matters.

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