Random Number Generator
Generate one or many random numbers in any range. Dice shortcuts for d4 through d100. History of last 10 results shown automatically.
Dice Shortcuts
How to use Random Number Generator
Generate a cryptographically random number within any range you specify — from a simple 1–10 roll to large integers for sampling and simulations. All generation uses the browser's Crypto API (window.crypto.getRandomValues) for true randomness, not a predictable pseudo-random seed. Supports single numbers, ranges, multiple draws, and unique (non-repeating) sets.
- Enter the minimum value (e.g., 1) in the "From" field.
- Enter the maximum value (e.g., 100) in the "To" field.
- Optionally set "How many numbers" for multiple results.
- Toggle "Unique" to prevent duplicate numbers in multi-number draws.
- Click Generate and copy individual results or the full set.
Your data never leaves your device — 100% private processing.
True random vs. pseudo-random numbers
Most programming language random functions (Math.random() in JavaScript, random.random() in Python) use a pseudo-random number generator (PRNG) — a deterministic algorithm seeded with a value like the current timestamp. PRNGs are predictable if the seed is known, making them unsuitable for security purposes. The Web Crypto API's getRandomValues() draws from the OS entropy pool (hardware events, timing jitter) to produce cryptographically secure random numbers — suitable for cryptographic keys, tokens, and any security-sensitive use. This tool exclusively uses the Crypto API.
Use cases by range
Range 1–6 simulates a standard die roll. Range 1–2 or 0–1 is a fair coin flip. Range 1–52 maps to a shuffled deck. Range 0–255 generates a random byte value. Range 1–1,000,000 is useful for lottery-style draws or raffle picks. For statistical sampling, generate unique numbers in a range to select random records from a dataset. For simulation modeling (Monte Carlo methods), generate large batches with specific distributions.
| Use case | Suggested range | Notes |
|---|---|---|
| Die roll (d6) | 1–6 | Standard board game die |
| Coin flip | 0–1 | 0 = tails, 1 = heads |
| Card draw | 1–52 | Map to rank × suit |
| Raffle pick | 1–N | Set N to number of entries |
| Byte value | 0–255 | Useful for color or data generation |
Glossary
- CSPRNG
- Cryptographically Secure Pseudo-Random Number Generator — suitable for security and cryptography applications.
- Entropy pool
- A collection of unpredictable data from hardware events used to seed cryptographic random number generators.
- Monte Carlo method
- A computational technique that uses random sampling to solve problems or estimate probabilities.
- Uniform distribution
- Each value in a range has an equal probability of being selected.
Related reading
Frequently Asked Questions
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Why use Random Number Generator?
- Cryptographically random generators for secure use cases
- Fully configurable output — length, charset, quantity
- Download or copy output in one click
- No data logged or stored — 100% private generation
Common use cases
- Generate a strong random password for a new account
- Create test data with realistic-looking names and emails
- Produce random numbers for a classroom lottery
- Generate Lorem Ipsum placeholder text for mockups
- Create unique UUIDs for software development
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