Utilities
Random numbers in any range
Generate one or many random numbers in any range, with or without repeats, using real cryptographic randomness.
For the best results: Set the range and how many you need; turn on no-repeats for draws and raffles. Numbers come from cryptographic randomness, not a predictable seed.
Runs entirely in your browser, what you paste is never uploaded, logged, or stored.
What is Random Number Generator?
Random Number Generator is a free online utility that generates random numbers in any range using cryptographic randomness, one at a time or in bulk. The math runs right in the page, so the numbers you enter stay on your device and are never sent anywhere. There is no account step, no limit on how many times you calculate, and it keeps working offline.
- ✦Runs entirely in your browser. Nothing you enter is ever uploaded
- ✦No account, no sign-up, and no data leaves your device
- ✦Works offline once the page has loaded
See it in action
A raffle needs 50 draws between 10 and 20, inclusive.
What you type
Min 10, Max 20, How many 50
What you get
Fifty numbers, every single one inside the range in testing, bounds included.
Tip: Numbers can repeat, as true random draws do; tick No repeats when every pick must be unique, keeping the count no larger than the range. The values come from the browser, nothing is fetched.
Use cases
What people use it for
Draw an unbiased winner for a giveaway or raffle in front of a live audience.
Generate a batch of random values for a classroom statistics exercise or a quick simulation.
Pick random sample rows for spot-checking a dataset or auditing invoices without selection bias.
Who uses Random Number Generator?
Competition organizers
run giveaways and prize draws where the winning entry must be chosen fairly and be seen to be fair.
Teachers and educators
demonstrate probability, sampling, and statistics with genuinely random numbers that students can generate for themselves.
Developers and testers
need quick random values for test data, seeds, and boundary-condition experiments during day-to-day development.
How it works
- 1Vary step 1 by tool shape using the existing FORM_TOOL_IDS set in app/(public)/[category]/[tool]/page.tsx. Form tools get "Set the options for what you need." and text tools get "Paste your text into the box." Where a tool's config makes it easy, name its own inputs instead. Steps 2 and 3 stay shared as they are.
- 2Your browser computes the result instantly. Nothing is uploaded anywhere.
- 3Copy the output; the tool keeps working even offline.
Tips for the best results
- Decide your range before generating so results cannot look cherry-picked.
- Generate in front of witnesses, or screen-record, when running a public draw.
- Expect duplicates in bulk output, because genuine randomness repeats itself.
- Number your entrants first, then draw against that fixed list.
- Use bulk generation for samples rather than clicking one value at a time.
FAQ
Frequently asked questions
What does cryptographic randomness mean here?
The numbers come from your browser's crypto-grade generator, the same source used for encryption keys, rather than the basic Math.random function. Cryptographic generators gather unpredictable entropy from the operating system, so their output cannot be reproduced or forecast even by someone who knows exactly how the code works. For draws where fairness matters, that distinction is everything.
Are the results truly uniform across my range?
Close enough that you will never notice. Every draw comes from the browser's cryptographic generator mapped onto your range. In principle a remainder mapping can lean a whisker towards the lower numbers, but for any everyday range that lean is far too small to detect, let alone to matter for draws, sampling or games.
Can anyone see or influence the numbers I generate?
No. Generation happens wholly on your device with no server round-trip, so there is no operator who could observe results or nudge them. Nothing is logged and no history is kept anywhere except your screen. For a prize draw, that also means there is no third party you would need to trust or disclose to entrants.
Can the same number appear twice when I generate in bulk?
Yes, unless you tick No repeats. Independent draws can repeat, exactly as rolling a die twice can produce two sixes; that is a property of genuine randomness, not a fault. For raffle-style draws where each entrant may win once, turn on No repeats and keep the count no larger than the range.
How is this different from picking numbers in my head?
Humans are famously poor randomisers: we avoid repeats, favor sevens, and steer away from the edges of a range, patterns well documented in psychology research. A cryptographic generator has no such preferences and no memory of previous picks. When fairness must be defensible, an algorithmic draw removes both bias and the appearance of bias.
How do I pick a random number between 1 and 100?
Enter 1 as the minimum and 100 as the maximum, then generate. Every integer from 1 to 100 inclusive carries an identical one-in-a-hundred chance. Watch the endpoints in DIY approaches, though: many hand-rolled formulas accidentally exclude the top value, a common source of subtly unfair draws.
Is Math.random good enough for a prize draw?
For casual use it is fine, but Math.random is a pseudorandom function that was never designed to resist prediction, and some older implementations were shown to be forecastable. A crypto-grade source costs nothing extra and removes the question entirely, which is why this generator relies on one.
Are random number generators actually random?
Numbers from an algorithm alone are pseudorandom. Cryptographic generators, however, are continually reseeded with physical unpredictability, such as timing jitter and hardware noise collected by your operating system, making their output indistinguishable from true randomness for every practical purpose, including draws, key generation, and statistical sampling.
Are there any usage limits?
None. Everything is generated locally in your browser, so there is no server cost, no metering, and no daily cap, use it as many times as you like, completely free.
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