# Random Number Generator

You may have wondered why predictable computers can generate randomness. In fact, most random numbers used in computer programs are pseudorandom, meaning that they are generated in a predictable way using a mathematical formula. This is great for many purposes, but it can’t be considered random, as you’d expect if you’re used to dice rolls and lottery draws.

## This version of the generator creates a random integer

**Lower Limit**

**Upper Limit**

## Generating a random, non-repeating number

**Lower Limit**

**Upper Limit**

A random number generator is a device that can generate one or more random numbers from a specific area. Random number generators can be hardware or pseudo-random.

A pseudorandom number generator is an algorithm for generating a sequence of numbers whose properties approximate the properties of sequences of random numbers. Computer random number generators are almost always pseudo-random number generators. However, the numbers generated by pseudo-random number generators are not really random. Similarly, our generators above are also pseudo-random number generators. Generated random numbers are sufficient for most applications, but they should not be used for cryptographic purposes. True random numbers are based on physical phenomena such as atmospheric phenomena, temperature, and other quantum phenomena. Methods that generate true random numbers also include compensation for potential distortions caused by the measurement process.