Random Number Generator

How to use the random number generator

1. Enter the lowest number you want in the Minimum field.
2. Enter the highest number you want in the Maximum field.
3. Set how many numbers you need, for example 6 for a lottery line.
4. Tick No repeats if the same number must not appear twice.
5. Press Generate. Press it again for a fresh draw.

What is a random number

A random number is a value picked from a defined range in a way that gives no clue about what comes next. Each draw stands on its own, so a number that just came up has exactly the same chance of coming up again. Over a large number of draws the results spread evenly across the range you set.

How this generator picks numbers

The tool uses the cryptographic random source built into your browser, with rejection sampling so that no number in the range is favoured by rounding. Nothing you type is sent anywhere. The whole draw happens on your own device, which means it also works offline once the page has loaded.

True random and pseudo random

Hardware generators read a physical source such as electrical noise or atmospheric noise. Software generators, including this one, run a mathematical routine seeded by the operating system. For picking a winner, rolling a value in a game or choosing a sample, a good software generator is more than enough.

Supported settings of the random number generator

Lowest Nr. and Maximum Nr.

These two fields set the pool the draw is taken from, and both ends are included. A range of 1 to 100 can return 1 and can return 100. If you type a minimum that is larger than the maximum the tool swaps them for you rather than returning an error, so a slip of the keyboard never costs you a draw.

Generate from a range

A range is simply the pool the draw comes from, and everything on this page starts there. The quick range buttons cover the pools people ask for most, from 1 to 10 up to 1 to 1000, and selecting one fills both fields and draws straight away. For anything else, type your own lowest and highest value and the highlighted button clears, which tells you a custom range is in force. Ranges can start below zero, so a pool such as minus 50 to 50 works exactly the same way.

You can even set how many numbers to generate

One draw can return between 1 and 1000 numbers. A single result is shown as one large number. Anything above that is shown as a grid of value chips with a summary line above it giving the count, the lowest value drawn, the highest value drawn and the average, which is a quick sanity check that the spread looks even.

Create random numbers

Each number is created the moment you press generate, drawn fresh from the range you set. Nothing is picked from a stored list and nothing repeats a previous session, so two people using the same settings at the same time will still see different results. By default numbers are drawn independently, which means the same value can turn up twice in one batch, and that is the correct behaviour for anything dice like. Switch on no repeats and each value is taken out of the pool once it appears, which is what raffle tickets and lottery lines need. A unique draw can never return more numbers than the range holds, so asking for 20 unique values from 1 to 10 is trimmed back to 10.

Number sorting from smallest to largest

Sorting changes only the display order, never which numbers were selected. The draw happens first and the sort is applied afterwards, so a sorted lottery line is exactly as random as an unsorted one. Leave it off when the order itself matters, for example when you are drawing first, second and third place.

Whole numbers only

Every result is a positive or negative whole number. There is no decimal mode on this page, because a decimal draw needs a precision setting that would clutter the main tool. If you need values such as 0.25 or 12.75, use the decimal generator listed under Numbers in the menu.

Practical limits

• Up to 1000 numbers in a single draw, which covers most sampling and testing jobs.
• Ranges are safe up to roughly 100 million on either side, including negative minimums.
• Unique draws are capped by the size of the range, never by the count you type.
• Results are held only until the next draw, so copy or download anything you need to keep.

Saving and reusing results

Two export routes sit next to every draw. Copy results puts the whole batch on your clipboard as a comma separated line, ready to paste into a message or a document. Download CSV writes one number per row with a header, which opens straight into a spreadsheet and is the better choice for large batches you plan to analyse or keep as a record of a draw.

Reading the summary line

On a multi number draw the summary shows the minimum, the maximum and the average of that batch. Over a large batch from 1 to 100 the average should sit near 50.5. A value close to that is a sign the spread is behaving. A single batch that lands well away from the middle is not a fault, it is ordinary variation, and it evens out as the batch grows.

Applications of a random number generator

• Giveaways and raffles. Number the entries, draw one number, announce the winner.
• Classrooms. Pick a student, choose the order of presentations, split a class into groups.
• Games. Replace a missing die, decide who starts, set a target score.
• Research samples. Select rows from a list without bias when you need a simple random sample.
• Lottery lines. Draw six unique numbers between 1 and 49 in one click.
• Decisions. Settle a tie, choose between options, break a deadlock fairly.
• Testing and demos. Fill a spreadsheet or a test data set with values in a set range.

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Frequently asked questions

More on how randomness works here.