Random Number Generator
Configuration
Results
History
Explore More Tools
The Science of Randomness
In a world governed by rules and algorithms, true randomness is a surprisingly difficult concept to master. Whether you are running a raffle, simulating a scientific experiment, or just trying to decide who pays for dinner, you need a source of numbers that is free from bias and predictability.
Our Advanced Random Number Generator (RNG) provides a robust platform for generating integers with mathematical precision. Unlike simple "pick a number" games, this tool allows for complex constraints like exclusions, sorting, and unique-only filtering, making it a professional-grade utility for data scientists, developers, and event organizers.
Gaming & Simulation
Randomness is the heart of gaming. From loot tables to hit probabilities, accurate RNG determines the outcome.
- Tabletop RPGs: Simulate d20, d10, or d100 rolls instantly.
- Loot Drops: Generate numbers to determine item rarity.
Statistics & Research
Researchers use Random Sampling to select unbiased groups for surveys and clinical trials.
- Simple Random Sampling: Pick 100 IDs from a database of 50,000.
- A/B Testing: Randomly assign users to Control or Variant groups.
True vs. Pseudo Randomness
Computers are deterministic machines—they follow instructions. Asking a computer to "be random" is contradictory. Therefore, most software uses Pseudo-Random Number Generators (PRNGs). These algorithms start with a "seed" (often the current time in milliseconds) and perform complex math to produce a sequence that looks random.
For most tasks, PRNGs are perfect. However, for cryptography, you need unpredictability. Our tool leverages the Web Crypto API (`crypto.getRandomValues`) which gathers entropy from system noise (mouse movements, keystrokes, thermal noise) to generate numbers that are virtually impossible to predict.
Why "Human Randomness" Fails
If asked to "pick a random number between 1 and 10," most people will pick 7. If asked to simulate a coin toss, humans rarely write "Heads, Heads, Heads, Heads" because it doesn't "feel" random, even though it is a perfectly valid random sequence.
This cognitive bias is why trusted third-party tools are essential for fairness. Whether you are auditing a financial process or drawing a raffle winner, using an algorithm removes the human element of subconscious selection bias.
Quick Reference: Modes
Like rolling dice. The number '5' can appear multiple times.
Like dealing cards. Once 'Ace of Spades' is dealt, it's gone.
Specific numbers are banned from appearing in the results.
Organize your random list to easily find if a number was picked.
Frequently Asked Questions
How random are these numbers?
We utilize the browser's built-in crypto.getRandomValues() method where supported, which generates cryptographically strong random values suitable for security-sensitive applications. For older browsers, it falls back to a high-quality pseudo-random number generator (PRNG).
Can I generate a list of unique numbers?
Yes. By creating a 'No Duplicates' list (also known as sampling without replacement), you ensure that once a number is picked, it cannot be picked again. This is ideal for assigning raffle prizes or shuffling a playlist.
How does the 'Exclusions' feature work?
The exclusions field allows you to blacklist specific numbers. If you enter '13, 666', the generator will mathematically skip these values while ensuring all other numbers in your range still have an equal probability of being selected.
What is the maximum range I can use?
You can specify any integer range within the JavaScript safe integer limits (+/- 9 quadrillion). However, generating a 'unique' list is limited by your device's memory since we must track used numbers.
Can I use this for official lottery drawings?
While our algorithm is mathematically fair and unbiased, for legal or high-stakes financial lotteries, you should use certified hardware random number generators (TRNGs) that rely on atmospheric noise or quantum phenomena, as required by local laws.
How do I generate decimal fractions?
This specific tool generates integers. To get a decimal (e.g., 0.55), generate a number between 1 and 100 and divide the result by 100 manually. We are adding a 'Decimal Mode' in the next update.
Is the data sent to a server?
No. All number generation happens locally in your web browser using JavaScript. No results are ever sent to or stored on our servers, ensuring your data remains private.
Why do I see the same number twice in 'Allow Duplicates' mode?
In a truly random sequence with replacement, repeats are expected and natural (like rolling a '6' twice in a row on a die). If you never saw repeats, it wouldn't be truly random—it would be a patterned sequence.
Can I download the results?
Yes, you can export your generated list as a .txt file using the 'Download' button. This is useful for saving large datasets for statistical analysis in Excel or Python.
What is the difference between Linear and Uniform distribution?
Our generator uses a Uniform Distribution, meaning every single number in your chosen range has the exact same probability of being chosen (1/N). There is no 'bias' towards the center or edges of the range.