Random Number Generator
A randomizer for any range: several numbers at once, a no-repeats mode. Free, no sign-up, and nothing leaves your device.
Press Space to generate
A normal draw is something your audience has to take on trust. Here the number is derived from your phrase, so anyone can repeat the draw and land on the same result.
- Announce the phrase before the draw — in the post, the caption or on air.
- Run the draw with that phrase.
- A viewer types the same phrase here and gets the same number.
Replaces the protected draw — the two cannot be on together.
History is kept in this browser only. We never see it and it is never sent anywhere.
This session
Counted in this browser, never sent anywhere
Press Generate — a histogram of every number in this session appears here, with the average and the spread.
Popular ranges
Ranges people type by hand most often — each one opens ready to go.
What this generator does
Type a lower bound, type an upper bound, press the button. You get one whole number, and every number in the range had exactly the same chance of appearing. That sounds trivial, and in a way it is — but almost every free generator on the web gets at least one part of it wrong, and the mistakes stay invisible until they matter.
Three things set this tool apart. It draws from your operating system's cryptographic entropy pool rather than a simple arithmetic formula. It corrects the rounding bias that silently favours the smallest numbers in a range. And it can prove after the fact that a particular result really did come from the inputs you published, which is what you need when there is a prize at stake.
Everything runs inside your browser. There is no server call when you press Generate, no account, no cookie that follows you and no log of what you produced. You can verify that claim yourself: open your browser's network inspector, generate a hundred numbers, and watch that nothing is sent.
If you type the same bounds every time, open the page that already has them set: 1 to 10, 1 to 20, 1 to 50, 1 to 100 or 1 to 1000.
Is a randomizer the same as a random number generator?
In everyday use, a randomizer is any tool that picks an option blind: a number, a winner from a list, an entrant among the comments. A random number generator is a randomizer whose options happen to be the whole numbers of a range you choose. So yes — the page you are on is a number randomizer, just named more precisely.
People look for it under a pile of different names: random number generator, number generator, number picker, number randomizer, random number generator online, or simply RNG. All of them lead to the same tool — the one above. The difference is habit rather than meaning: the short number generator is what you type when you only need a number, the word random gets added when the point is that nobody arranged the outcome, and RNG is the abbreviation players and programmers use for exactly the same thing.
The difference shows up when the thing you need to pick is a name rather than a number. There is no reason to number your entrants by hand: open the giveaway randomizer instead, which takes the whole list, draws winners and reserves, and hands your audience a proof link. And when the question needs a single answer rather than a number, there is yes or no.
Where people use it
🎁Prize draws
Number your entrants, draw a winner, and publish a link that lets anyone replay the exact same result. The protected giveaway page explains how the proof works.
🎓Classrooms
Call on students without favouring the front row, split groups, or hand out exercise numbers. Fullscreen mode puts the digits on the projector.
🎲Board games
A lost die is no longer a problem: there is a six-sided die and a d20, plus a no-repeats mode for drawing tiles without putting them back.
🏆Sport and lots
Assign lane numbers, decide starting order, pick who goes first. For lottery formats there is a ready-made 6 of 49 generator.
🧪Testing and samples
Pick random rows to audit, choose a sample from a numbered list, and for throwaway test accounts use the password generator, nickname generator and name generator.
🤔Making a decision
When two options are genuinely equal, stop agonising and let the number decide. The yes or no tool is the one-question version.
What you can do with a result
- Fullscreen presentation. One press fills the screen with the number so a whole room can read it — built for teachers at a projector, hosts on stage and streamers. No other generator has this.
- Repeatable draw. Announce a code phrase before the draw and the result becomes reproducible: every viewer types the same phrase and gets the same number.
- No-repeats mode. Draws without replacement, which is what you actually want when you are handing out unique numbers rather than rolling a die.
- Live session statistics. A histogram of everything you have drawn, with average and spread, so you can see for yourself that the distribution is flat.
- CSV export. Useful when you generated fifty numbers and need them in a spreadsheet.
- Read out loud. The result is spoken in the language of the page — helpful for accessibility and when your hands are busy.
What makes a draw fair
Fairness is not one property but three, and tools usually deliver only the first. The source has to be unpredictable, the conversion into your range has to be unbiased, and the procedure has to be checkable by someone who does not trust you. A generator can be perfectly random and still useless for a giveaway, because the audience has no way to tell the difference between an honest draw and a staged one.
Two separate modes cover that third property, and there is no reason to run both at once. Protected draw is for the ordinary case: the server picks and signs the number, and you hand your audience a link that shows them exactly the result you saw. Repeatable draw is for when a viewer has to check the draw with their own hands: the result is derived from a code phrase, so anyone who knows it gets the same number. Announcing the phrase before the draw keeps unpredictability intact too — until it is named, nobody can predict the outcome.
How true randomness works
A computer is a machine built to be predictable, which makes producing a genuinely unpredictable number a surprisingly awkward request. There are two families of answers, and the difference between them matters more than most people expect.
Where the unpredictability comes from
Your operating system maintains an entropy pool: a reservoir of noise collected from physical events it cannot anticipate. The precise timing of keystrokes, jitter in disk and network interrupts, fluctuations in hardware counters, and on modern processors a dedicated instruction that samples thermal noise inside the silicon itself. None of that is a formula. It is measurement of the physical world, and that is what makes it unpredictable rather than merely complicated.
This generator asks the browser for bytes from that pool through the Web Crypto API, using
crypto.getRandomValues(). It is the same source your browser uses to create the encryption keys
protecting your bank session.
Why Math.random is not enough
Most quick generators call Math.random(). It is fast, convenient, and a pure arithmetic formula
with a hidden internal state. Feed it a starting value and it produces the same sequence every time. Observe
enough of its output and the state can be reconstructed, after which every future value is known in advance.
For shuffling background images that is fine. For deciding who receives a prize it is not, and browser vendors
say so explicitly in their own documentation.
The rounding bias almost nobody corrects
Here is the mistake that hides in plain sight. Suppose you have random bytes from 0 to 255 and you want a number from 1 to 100. The obvious move is to take the remainder after dividing by 100 and add one. It looks harmless, and it is wrong: 256 does not divide evenly into 100, so the values 1 to 56 come up slightly more often than 57 to 100. The bias is small, roughly one part in two hundred, but it is systematic, it never averages out, and across a large draw it is real.
We avoid it with rejection sampling: the generator discards any value that falls in the uneven tail and simply draws again. That costs a few microseconds and gives a distribution that is exactly uniform rather than approximately uniform.
Provable results, when a prize is involved
Unpredictable and provable are opposites, and you cannot simply have both. The trick is doing them in the right order. Turn on repeatable draw and the generator stops drawing from the entropy pool and instead derives the result from a code phrase you can announce publicly.
The honest way to use it is to announce the phrase first and draw second. People typically use something like tomorrow's closing price of a stock, or the number of a future lottery draw. Until the phrase is named nobody knows the outcome, including you, because the value does not exist yet. Once it becomes public you run the draw, and any viewer types the same phrase and arrives at the same winner.
If your audience does not need to check it by hand, protected draw is simpler: the server picks and signs the number, and you only have to share the link to the result page.
Why the same number keeps coming up
This is the most common complaint about every random number generator ever built, and in almost every case the generator is innocent. Real randomness clusters. It has no memory, so it has no reason to avoid a value it just produced. Roll a die six times and the chance of seeing all six faces is only about one and a half percent; the overwhelmingly likely outcome is that something repeats and something is missing.
Human intuition expects an even sprinkle and reads clustering as a malfunction. If you need every value to appear exactly once, that is a different requirement with its own mode: switch to No repeats and the generator draws without replacement, removing each number from the pool as it comes out.
Frequently asked questions
How is a randomizer different from a random number generator?
Only in how people say it. Randomizer is the casual word for any tool that picks an option blind; a random number generator is a randomizer whose options are the whole numbers of a range. When the thing you need to pick is a name rather than a number, use the giveaway randomizer instead: it works from your entry list and produces a proof link.
Is this actually random, or does it just look random?
It is drawn from your operating system cryptographic entropy pool through the Web Crypto API — the same source used to generate encryption keys. That pool is fed by physical noise such as interrupt timing and hardware thermal sampling, not by a formula. We also apply rejection sampling so the conversion into your range introduces no bias.
Can anyone predict or influence my result?
Not in normal mode. The draw happens on your device using entropy we never see, and nothing is transmitted. In repeatable-draw mode the result becomes deliberately reproducible — that is the point — so anyone who knows the code phrase can compute the same answer. Use that mode only when you intend to announce the phrase.
Why did the same number appear twice in a row?
Because that is what randomness looks like. Each draw is independent and has no memory of the last one, so repeats and gaps are expected rather than suspicious. If you need every value to appear exactly once, switch to No repeats, which draws without replacement.
What is the biggest range I can use?
Anything up to roughly nine quadrillion in either direction, and negative bounds are fine. Beyond that browsers lose whole-number precision, so we cap the input rather than return a number that is quietly wrong.
Is it free, and do I need an account?
Free with no limits and no account. The site is funded by advertising placed away from the tool. There is no paid tier, no watermark and nothing to unlock.
Does it work offline?
Yes. Once the page has loaded the generator needs no connection, because the computation happens locally. Add the page to your home screen and it keeps working on a plane or in a basement.
Do you store the numbers I generate?
No. Nothing is sent to a server, so there is nothing to store. Your session statistics and draw history live in your browser local storage and are erased when you clear site data.
Can I use this for a giveaway with a real prize?
Yes, and for that case use the protected giveaway tool rather than this page. It locks the entry list with a fingerprint before the draw and produces a verification page your audience can check themselves.
How is this different from the Google random number generator?
Google shows a plain spinner right in the search results — two bounds and a button — and that widget is what most people mean when they search for the Google number generator. For a number to move a board game along it is enough; for anything else it is not. Here you get several numbers at once, a no-repeats mode, a full-screen display for an audience, CSV export, session statistics and a proof link for a draw with a prize.