Random Number Generator

The Random Number Generator is a free online tool that generate cryptographically secure random integers, decimals, gaussian values, dice rolls, and lottery picks — all in your browser.. It runs entirely in your browser with no installation or sign-up needed.

They are cryptographically secure pseudo-random via Web Crypto (crypto.getRandomValues) — the same primitive used for key material, suitable for games, simulations, and most security-sensitive uses.

Small ranges use a partial Fisher-Yates shuffle; larger ranges use a Set-backed rejection loop. The tool validates max-min+1 >= count before generating.

Box-Muller transform: z = sqrt(-2*ln(u)) * cos(2*pi*v), then scaled by your mean and standard deviation.

Yes, the Random Number Generator is 100% free with no registration, no hidden fees, and no usage limits. All processing happens locally in your browser, ensuring complete privacy.

Absolutely. The Random Number Generator processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the Random Number Generator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the Random Number Generator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The Random Number Generator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Modulo bias happens when you map a random source onto a range that doesn't divide evenly into it. If you take a 32-bit random value and use the remainder (modulo) to fit a range, the lowest numbers in that range can come up slightly more often, because they have one extra way to be produced. Over many draws this skews your distribution and quietly breaks fairness. This generator avoids it with rejection sampling: it discards any draw that would fall into the uneven leftover region and retries, so every integer between your minimum and maximum is equally likely. That matters for prize draws, blind experiment assignment, and shuffling, where a tiny bias is unacceptable. Set your range and count in the Integer tab and press Generate for unbiased results.

Truly random numbers come from a physical, non-deterministic source such as atmospheric noise, radioactive decay, or thermal jitter — genuine entropy from the real world. Cryptographically secure pseudo-random numbers (CSPRNG), which this tool produces via the Web Crypto API, are generated by an algorithm seeded from the operating system's entropy pool. They are deterministic in principle, but seeded and designed so the output cannot be predicted or reproduced without the internal state, which is computationally infeasible to recover. For games, simulations, sampling, raffles, and most security tasks, a CSPRNG is indistinguishable from true randomness and far faster and more available. Only specialized cryptographic hardware or scientific work typically needs a true hardware source. For everyday fair, unguessable draws, open any tab and generate — the numbers are secure by default.

NdX notation is a compact way to describe a dice roll: N is how many dice you roll and X is how many sides each die has. So 2d6 means roll two six-sided dice, 4d20 means roll four twenty-sided dice, and 1d100 means roll a single hundred-sided die. It is the standard shorthand in tabletop games like Dungeons and Dragons and board game rulebooks. In the Dice tab you set the number of dice (up to 1,000) and the sides per die (from 2 to 10,000), then generate to see each die's result. Every die is rolled independently with the same cryptographically secure source, so the outcomes are fair and unbiased — no weighted or loaded dice. Pick the Dice / Lottery tab, enter your dice count and sides, and roll.

A uniform distribution makes every value in your range equally likely — drawing a number from 1 to 100 gives each number the same chance, like rolling a fair die. A Gaussian, or normal, distribution instead clusters most values near a central mean and produces extremes only rarely, forming the familiar bell curve. You control it with two settings: the mean (μ), which is the center, and the standard deviation (σ), which is the spread. Roughly 68% of generated values land within one σ of the mean and about 95% within two σ. This is the right choice when you are modeling real-world measurements like heights, test scores, or measurement error, which naturally bunch around an average. Use the Decimal tab for uniform numbers, or the Gaussian tab to set your mean and standard deviation and sample a realistic bell curve.

Yes. The Dice / Lottery tab includes a lottery mode that picks N unique numbers from 1 to M, exactly like a real draw where the same ball cannot come up twice. You set how many numbers to pick and the maximum value — for a 6-from-49 game you would pick 6 from a range of 49 — and the results are returned sorted in ascending order for easy reading. Because every selection draws from the Web Crypto secure random source and rejection sampling keeps the odds even, no number is favored and the picks cannot be guessed or reproduced. The tool also checks that your request is possible, so it won't try to draw more unique numbers than the range allows. It is genuinely random rather than a lucky guess, which makes it ideal for personal quick picks. Open the Dice / Lottery tab, choose lottery mode, and generate your numbers.