Random Number Generator

Generate random numbers in any range.

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Input
Output
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About random number generator

Random Number Generator is a small tool that does one job while you watch. Nothing is saved, so a reload gives you a clean start.

The tool is a few kilobytes of JavaScript, not a service. That is why it can promise your data stays put and actually mean it.

You will find it under Everyday sums, alongside 13 other tools for the same sort of job.

Supports integers and decimals, single or batch generation up to 1000 numbers.

How to use it

01
Start it
Every control is on the tool itself. Keyboard shortcuts, where there are any, are listed beside it.
02
Watch it run
It updates in the page as you go. Nothing is sent anywhere, so it keeps working with the network off.
03
Close when done
Nothing is stored between visits. Reloading gives you a clean start rather than picking up where you left off.

Examples

Roll 5 Dice
Generate 5 random integers between 1 and 6
Input
min: 1
max: 6
count: 5
integers: true
Output
6, 1, 6, 5, 1

Questions

Does Random Number Generator work offline?+

Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.

Does it remember anything between visits?+

No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.

Is it accurate?+

Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.

Does it make a sound?+

Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.

Can I use Random Number Generator on a phone?+

Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.