Picking a Number Without Bias
Ask a person to "think of a number between 1 and 100" and the answers bunch up — 7, 42, and 77 turn up far more often than chance would allow. A random number generator removes that bias entirely: every value in your range is equally likely on every press, with no memory of what came before. Set the bounds, choose how many numbers you want, and let the math do the deciding.
Sample run: five unique picks from 1 to 100
Enter 1 in Min and 100 in Max, set the count to 5, and tick No duplicates, then press Generate (or the spacebar). A run like that returns a draw such as 7, 23, 51, 68, 92 — five distinct whole numbers spread across the range. Generate again and the five values change completely; with duplicates allowed, the same number could appear more than once in a single draw.
True Random vs. Pseudo-Random
There are two main categories of RNGs:
True random number generators (TRNG)
TRNGs derive randomness from physical phenomena such as atmospheric noise, radioactive decay, or thermal fluctuations. Because they rely on unpredictable physical processes, they are considered truly random. Hardware security modules and services like random.org use TRNGs.
Pseudo-random number generators (PRNG)
PRNGs use a deterministic algorithm to produce sequences of numbers that appear random. Given the same starting seed, a PRNG will always produce the same sequence. Modern PRNGs — including the one in every major web browser — are designed so their output passes rigorous statistical tests for uniformity and independence. For games, raffles, simulations, and everyday picks, a PRNG is indistinguishable from true randomness.
How Math.random() Works
This tool uses JavaScript's built-in Math.random() function. It returns a floating-point number ≥ 0 and < 1. To produce a random integer between a min and max (inclusive), the formula is:
Math.floor(Math.random() × (max − min + 1)) + min
Modern JavaScript engines implement Math.random() using the xorshift128+ algorithm, which has a period of 2128 − 1 and passes the BigCrush statistical test suite. It is fast, uniform, and more than adequate for any non-cryptographic purpose.
Common Uses of Random Numbers
Games and entertainment
Dice rolls, card shuffles, loot drops, procedural level generation — random numbers are the backbone of unpredictable gameplay.
Raffles, giveaways, and lotteries
Assign each entrant a number, set the range, and generate a winner instantly. Using a no-duplicate mode ensures every entrant has a fair, unique draw.
Statistics and sampling
Random sampling is fundamental to surveys, A/B tests, and scientific experiments. Generating a set of unique random indices selects an unbiased sample from a population.
Education
Teachers use random number generators to create quiz questions, randomly assign students to groups, and demonstrate probability concepts in the classroom.
When Not to Rely on This Generator
This tool is built for everyday randomness — games, draws, sampling, classroom demos — and it is excellent at that. It is the wrong choice in three places. First, anything cryptographic: passwords, encryption keys, security tokens, and session identifiers need a dedicated CSPRNG, because Math.random() is fast but predictable to a determined attacker and must never seed a secret. Second, regulated or official draws: a licensed lottery or a legally binding raffle needs a certified, auditable random source, not a web page. Third, exact distributions for serious statistics: the output is uniform and more than good enough for sampling, but if your study depends on a specific seeded, reproducible sequence you should use a documented statistical library. For everything in between, it is fair, fast, and unbiased.
Random Number Questions, Answered
How does a random number generator work?
This tool uses JavaScript's Math.random() function, which generates a pseudo-random floating-point number between 0 (inclusive) and 1 (exclusive). That value is then scaled to your chosen range using the formula: Math.floor(Math.random() * (max - min + 1)) + min. The result is uniformly distributed across the range.
Is this random number generator truly random?
The numbers produced are pseudo-random, not cryptographically random. The underlying algorithm (typically xorshift128+ in modern browsers) produces sequences that are statistically indistinguishable from true randomness for everyday purposes such as games, picks, raffles, and simulations. For cryptographic or security-sensitive applications, a dedicated CSPRNG should be used instead.
How do I generate a random number between 1 and 10?
Set the Min field to 1 and the Max field to 10, then click Generate (or press the spacebar). The tool will instantly display a random whole number from 1 to 10, inclusive.
How do I generate a random number between 1 and 100?
The default range is already 1 to 100. Simply open the tool and click Generate or press the spacebar to get a random number from 1 to 100. You can change the range at any time by editing the Min and Max fields.