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Random Number Generator and RNG Tutorial

RNGs are used in computer games, data encryption, monte carlo simulations, music, art, raffles and for winning lottery numbers!
  1. Select a Range
  2. Hit Generate!
Min:     Max:    

(For integers with possible values from 0 to 100.)


Your random number is... 
face pic by Paul Alan Davis, CFA
Updated: January 22, 2018
Want to learn more about RNGs? Keep reading or poke around at our other tutorials.

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How Does a Random Number Generator Work?


Most people just want a quick random number without having to think about it. And that's great. Then there are those who can't control their curiosity. We want to "know what we don't know", and at the same time we don't have time for a deep dive. So if that sounds like you, then you have found the right place.

You might not know, but a random number generator, especially one that sits on your computer, directly impacts your life on a daily basis, especially for computer security. Besides that, RNGs have other not so obvious uses.

Some don't take RNGs for granted and devote their entire professional career to the details. These include scholars, cryptographers and even hackers.

Random number generators for finance and investment applications are quite common. Statistical tests often require random numbers in the process of forecasting returns and volatility.

How does a computer generate a random number and is it truly random?

A computer can generate what is called a pseudo-random number by either calculating one with an algorithm or by accessing a table of numbers from a file. This approach isn't flawless in an academic sense but is suitable for most applications.

Pseudo-random numbers

A Pseudo-Random Number Generator, or PRNG, involves selecting "pseudo" or near-random numbers. As its name implies, results are not as random as you might expect from a roll of dice or a lottery drawing where balls fall from a cage.

Instead, a computer uses either an algorithm or table and when it pulls a string of random numbers it generally starts at what is called a seed, or starting point. Because of this, numbers will eventually repeat, but not often enough for us mere mortals to care.

It is in computer encryption that random number generation takes on added importance. And in academia, especially in studies associated with statistical probability, it is important that the shape of a distribution appears random and there is no relationship between successive numbers.

At the same time, the fact that numbers can be duplicated, from the "seed", means that academic results can be reproduced, which is important for peer-reviewed studies.

So while not perfect, there are benefits to using a computer to pick random numbers. They are cheap, efficient and readily available.

What are the technical details of this random number generator?

This is a client-side RNG, meaning it is generated from your browser, so it isn't accessing a FactorPad server. It also isn't pulling numbers from physical observations like atmospheric noise or radioactive decays, instead it is using an algorithm referred to by your browser.

To me this is good enough. The only time I would seek another source for random numbers would be for a PhD dissertation or for a computer security application. In fact, on the latter point, browser developers, like Mozilla or Google often warn that their algorithms do not provide random numbers that are cryptographically secure.

The tool above is a simple and free RNG used to pick one integer at a time. I should add a technical detail that I wrote it so it would pick numbers that are "inclusive", meaning that if you selected a range from 1 to 10, then 10 would be included as a possible random result.

Why should we care?

Here you will find tutorials and reference material in the fields of Finance and Technology. We bump into random numbers quite frequently. We love learning about statistics, data, numbers, probablilities and sharing that in a way that helps readers and viewers learn faster.

Our content is free and every page has the same structure, so while you are here, please have a look around. Bookmark this page so for that random occurance when you need a random number, you will have a place to go. ;]

My goal was to create the easiest random number generator online, and hopefully provide you with a free bonus...a bit of random knowledge.

Happy Learning!

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