Calculators

Statistics

About Random Number Generators

There are two main types of random number generators: pseudo-random and true random.

A pseudo-random number generator (PRNG) is typically programmed using a randomizing math function to select a "random" number within a set range. These random number generators are pseudo-random because the computer program or algorithm may have unintended selection bias. In other words, randomness from this type of computer program is not necessarily a truly random event.

A cryptographically secure pseudo-random number generator (CSPRNG) is a more secure PRNG designed to generate outputs that are computationally unpredictable. Like PRNGs, CSPRNGs are programmed algorithms. However CSPRNGs sample randomly occurring environmental noise in an operating system and use this to seed the algorithm to produce random numbers.

A true random number generator (TRNG) relies on randomness from a physical event that is external to the computer and its operating system. Examples of such events are blips in atmospheric noise, or points at which a radioactive material decays. A true random number generator takes information from these types of unpredictable events to produce a truly random number.

The CalculatorSoup^® random number generator is a cryptographically secure PRNG. It uses the random_int() function in PHP to generate random numbers which pass the "next-bit test." This means that it's statistically impossible to predict future output by knowing previously generated numbers. A random number generator programmed with a dedicated CSPRNG function is computationally indistinguishable from a true random number generator.

How to Generate Random Numbers

1. What is your range? Set a minimum number and a maximum number. The random number(s) are generated given your range of numbers, with the min and max numbers included.
2. How many numbers? Specify how many random numbers to generate.
3. Allow repeats? If you choose No your random numbers will be unique and there is no chance of getting a duplicate number on that draw. If you choose Yes the random number generator may duplicate or repeat a number in your set of numbers.
4. Sort numbers? If you do not sort your random numbers they will display in the sequence in which they were generated. Or you can choose to sort your list of random numbers as ascending, lowest to highest or descending, highest to lowest.
5. How many sets? You can input how many sets of random numbers you want to generate given the range and quantity of numbers specified above. Within this option you should indicate whether numbers are re-used between sets, or if numbers are removed from the pool of numbers once they are selected.

If you need to copy and paste your random numbers choose how you want the calculator to list the random number output. This way you can copy and paste your random numbers in your preferred format. Choose to separate numbers by commas and spaces, or spaces with no commas. Or choose to list the random numbers as a single spreadsheet row or a single spreadsheet column.

If you need to include letters in a random character set see the CalculatorSoup^® Random Number and Letter Set Generator.

Example: Generate a Random Number to Use as a PIN.

To generate a 6-digit PIN with or without duplicating digits choose the following settings:

• Min = 0
• Max = 9
• Generate 6 numbers
• Allow repeats = yes or no
• Sort numbers = Do not sort

Do it: Generate a 6 digit PIN without duplicates

Example: Randomize a Set of Numbers

Say you have a group of 10 people represented by the numbers 1 to 10. You want to shuffle them into a random order of selection for an event.

Choose the following settings to randomize order of selection:

• Min = 1
• Max = 10
• Generate 10 numbers
• Allow repeats = no
• Sort numbers = Do not sort

Do it: Randomize the order of a set of numbers, 1 to 10

Example: Randomly Choose One Number From a Range of Numbers

Say you want randomly select one number from 1 to 10, like drawing a number out of a hat.

Choose the following settings:

• Min = 1
• Max = 10
• Generate 1 number
• Allow repeats = no
• Sort numbers = Do not sort

Do it: Random number generator 1 to 10

Also try: Random number generator 1 to 100

Example: Lottery Number Generator

You want to generate numbers for lottery tickets. You need to choose 6 numbers from a pool of 1 to 56 without reusing numbers. You'd like 5 sets of lottery numbers, and numbers can be reused across the sets.

Choose the following settings in the random number generator:

• Min = 1
• Max = 56
• Generate 6 numbers
• Allow Repeats = no
• Sort Numbers = low to high
• Generate 6 sets
• Numbers are reused

Do it: Generate 5 sets of 6 lottery numbers from a range of 1 to 56