Need a random number? This free random number generator produces random integers between any minimum and maximum you specify — one number or a whole list, with or without repeats. The numbers are generated using your browser’s cryptographically secure random source, which means they are far more unpredictable than the pseudo-random functions used in many simpler tools. Set your range, choose how many numbers you want, and press Generate. The result is instant, private, and free.
How to Use the Random Number Generator
- Enter the minimum value (the lowest number that can appear).
- Enter the maximum value (the highest number that can appear).
- Enter how many numbers to generate.
- Optionally tick no repeats to ensure each number appears only once.
- Press Generate and copy your results.
How It Works
This tool uses the browser’s built-in crypto.getRandomValues() API — the same cryptographically secure random number generator (CSPRNG) used for generating encryption keys and security tokens. A CSPRNG is seeded by genuine entropy sources (hardware events, timing, and operating system randomness), making its output statistically unpredictable. Standard Math.random() in JavaScript is a pseudo-random number generator (PRNG), which is faster but deterministic from its seed and not suitable for anything requiring real unpredictability. For picking lottery numbers, running draws, or any use where fairness matters, a CSPRNG is the right tool.
Worked Example
You are running a raffle with 200 ticket holders (numbered 1 through 200) and need to pick 5 winners without repeating a number. Set minimum to 1, maximum to 200, count to 5, and check no repeats. Press Generate. The tool produces five unique random integers from that range, using the cryptographic RNG, so every ticket has an equally fair chance of being drawn.
Why Use a Random Number Generator?
Random numbers have an enormous range of applications. Drawing a winner from a group: instead of folding paper slips, enter the range of participant numbers and generate one. Games and simulations: dice rolls, card shuffles, and coin flips can all be simulated with a random integer in the right range (1–6 for a die, 1–52 for a deck). Statistical sampling: if you need to randomly select records to audit or survey respondents to interview, generating a list of random indices makes the sample unbiased. Education: teachers use random numbers to assign groups, randomize quiz questions, or pick students for participation. Creative decisions: randomness can break creative blocks by forcing a choice you would not have made deliberately.
Random Numbers Without Repeats (Sampling Without Replacement)
When you tick the no-repeats option, the tool samples without replacement — once a number is drawn, it cannot appear again. This is the correct mode for any fair draw, lottery, or raffle, because repeats would give some numbers a higher effective probability of winning. Sampling with replacement (repeats allowed) is appropriate when each draw is truly independent, such as simulating dice rolls where the same face can legitimately appear on consecutive rolls. Both modes are one click apart on this tool.
Pseudo-Random vs. Cryptographically Secure Random
Most programming languages have a standard random function that is fast and produces numbers that look random. These are pseudo-random number generators: they use a mathematical algorithm starting from a seed value, and if you know the seed and the algorithm, you can predict every number in the sequence. That is fine for simulations and games, but it is problematic when fairness or security depends on unpredictability. A cryptographically secure generator uses real-world entropy that an attacker cannot predict or reproduce. This generator uses the CSPRNG, so it is appropriate for draws, giveaways, and any situation where the randomness needs to be genuinely fair and verifiable.
Frequently Asked Questions
Is the random number generator truly random?
It uses the browser’s cryptographically secure random number generator (crypto.getRandomValues()), which draws on real hardware entropy. This makes it statistically unpredictable and suitable for fair draws and lotteries, unlike simple pseudo-random functions.
Can I generate a list of unique random numbers?
Yes. Tick the no repeats option and enter how many numbers you want. The tool will generate a list of unique integers within your specified range, with each number appearing at most once.
Is the random number generator free and private?
Yes — it is completely free, requires no signup, and runs entirely in your browser. No numbers or inputs are sent to any server.