RandomNr

Advanced and Statistical

Random Number Generator, Normal Distribution

Draw values that follow a normal distribution with the mean and standard deviation you set.

Normal Distribution Generator

0.42

Mean 0, sd 1

Distribution

How many values

Draw values from a bell curve

This tool generates numbers that follow a normal distribution, the familiar bell curve, around a mean and spread you set. Most values land near the mean, and fewer appear as you move out toward the tails. Set the mean, the standard deviation and the decimals, then generate a batch.

Mean, spread and the method

The mean is the centre and the standard deviation is how wide the curve is: about two in three values fall within one standard deviation of the mean. The tool uses the Box Muller method, which turns pairs of uniform random numbers from the cryptographic source into normally distributed values.

Reading the sample statistics

For a batch the tool shows the sample mean and standard deviation, which sit close to the values you set and get closer as the batch grows. That is a quick check that the spread is behaving as a normal distribution should.

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Frequently asked questions

What is a normal distribution

A bell shaped spread where values cluster around a central mean and thin out toward the edges. Heights and measurement errors often follow it.

What do mean and standard deviation do

The mean sets the centre and the standard deviation sets the width. A larger standard deviation spreads the values wider.

How are the values generated

With the Box Muller method, which converts uniform random numbers from the browser cryptographic source into normally distributed ones.

Can the values be negative

Yes. A normal distribution extends both ways from the mean, so with a mean of 0 you will see negative and positive values.

Is it free

Yes, free and with no sign up.

Related generators

For a flat spread instead of a bell curve, use the random number generator, or draw a fair sample with the random sample generator.