Random Number Generator

How to use Random Number Generator

1. Enter the minimum and maximum. Both ends are included in the possible results.
2. Choose how many numbers you need, from 1 to 10,000.
3. Tick No repeats for unique numbers, or Decimals to generate fractional values with 1 to 6 places.
4. Press Generate, then copy the result with your preferred separator.

Why randomness quality matters

Many simple generators use a pseudo-random formula that is fast but predictable if you know its internal state. That is fine for animation but poor for draws where fairness matters. Browsers also provide a cryptographically secure generator that draws on unpredictable system entropy, and this tool uses that one.

A second subtle issue is bias. Taking a random 32-bit number and applying a remainder to fit your range slightly favours smaller values unless the range divides evenly. The generator discards the few values that would cause this and draws again, so each outcome has exactly the same probability.

Common ways to use it

• Pick winners for a giveaway by numbering entries and drawing unique numbers.
• Choose a random page, question or exercise number for study.
• Create sample data or test values within a range.
• Make fair decisions, such as who goes first, by drawing a number.
• Generate decimals for quick simulations or illustrative figures.

Unique numbers and decimals

With No repeats ticked, each number can appear only once in the result, like drawing balls without putting them back. With decimals, the range is split into steps of the chosen precision. For two places, 0 to 1 has 101 possible values: 0.00, 0.01 up to 1.00.

Remember that random does not mean evenly spread. A short list may contain clusters or repeated digits by chance. Over many draws the results balance out, but a small sample rarely looks perfectly tidy.

Limits

The tool supports ranges up to about nine quadrillion integers and up to 10,000 results per click. Results are not saved, so copy anything you need before leaving the page.

Why use this random number generator tool

• Truly unbiased. Rejection sampling removes modulo bias, so no number in your range is favoured over another.
• Unique mode. Draw without replacement, such as raffle numbers, with a clear message if the range is too small.
• Integers or decimals. Generate whole numbers or values with a fixed number of decimal places.
• Works offline. Everything runs in the page, so nothing you generate is sent anywhere.

Frequently asked questions

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