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Random Number Generator — Cryptographically Secure Integers

Generate cryptographically random integers — range, count, unique-only and decimal / binary / octal / hex output.

Free No signup Client-side Privacy friendly Updated

How to use

  1. 1 Set Min, Max and Count.
  2. 2 Optionally toggle Unique values to draw without replacement.
  3. 3 Pick a base (decimal / binary / octal / hex) and separator.

Why use this tool

  • Cryptographically secure — uses Web Crypto, not Math.random().
  • Unique mode is rejection-sampled — uniform across the range.
  • Output in 4 bases — drop straight into your code.
  • Pure client-side — your numbers never leave the browser.

Frequently asked questions

How are these random?

They come from <code class="font-mono text-xs">crypto.getRandomValues()</code> with unbiased uniform sampling — modulo-bias is rejected on the fly.

What is the maximum count?

Up to 10,000 numbers per click. Unique requires count ≤ range size.

Why are negative numbers allowed?

Min and Max are signed integers — you can use any whole-number range.

What is Random Number Generator?

A Random Number Generator is a tool that produces random integers in the browser using a cryptographically strong random source. It lets the user set a range and count, restrict results to unique values, and display output in decimal, binary, octal, or hexadecimal. All generation happens client-side with no signup or server involvement.

Features

Cryptographically strong randomness

Uses crypto.getRandomValues() to draw 64 bits per candidate and rejects values above the largest multiple of the range, avoiding the modulo bias that a naive Math.random() * range approach would introduce.

Decimal, binary, octal, or hex output

Each generated integer can be formatted as base 10, base 2 (0b prefix), base 8 (0o prefix), or base 16 (0x prefix, uppercase digits).

Unique-only mode

Prevents duplicate values in the output. Ranges up to 100,000 use an in-memory Fisher-Yates shuffle; larger ranges fall back to reservoir sampling with a Set until the requested count of distinct values is collected.

Configurable count and separator

Generates from 1 up to 10,000 numbers per run, joined by a newline, comma, or space, ready to copy directly from the output box.

Example

Input

min=1, max=100, count=10, unique=true, base=10, separator=comma

Output

7, 42, 88, 15, 63, 29, 91, 3, 56, 74 (10 unique integers between 1 and 100, comma-separated)

Common use cases

  1. 1

    Raffle and giveaway draws

    Generate a unique set of winning ticket numbers within a known range without repeats.

  2. 2

    Sampling and test data

    Produce batches of random integers in decimal or hex for seeding test fixtures, load-testing IDs, or statistical sampling.

  3. 3

    Games and tabletop tools

    Roll ranges (e.g. 1-6, 1-20) repeatedly or draw a fixed count of non-repeating numbers for lottery-style games.

Summary

Generates random integers in a user-set [min, max] range using the browser's Web Crypto API (crypto.getRandomValues) with rejection sampling for unbiased uniform output, rather than Math.random(). It supports up to 10,000 values per run, an optional unique-only mode (Fisher-Yates shuffle for ranges up to 100,000, reservoir sampling via Set for larger ranges), and decimal, binary, octal, or hexadecimal formatting. Everything runs client-side in JavaScript — no numbers are sent to a server.

Category
Creator
Pricing
Free
Privacy
Browser-based
Signup
Not required

References

Privacy

Your data never leaves your browser unless explicitly stated. Random Number Generator runs entirely client-side — no server upload, no logging, no tracking of your input.

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