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3 min read6 Steps

How to Calculate Standard Deviation: Step-by-Step Guide

Learn to calculate variance and standard deviation manually

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Step-by-Step Instructions

1

Calculate the Mean

First, calculate the mean of your dataset by summing up all the values and dividing by the number of values. For example, if your dataset is [1, 2, 3, 4, 5], the mean would be (1 + 2 + 3 + 4 + 5) / 5 = 3.

2

Calculate the Deviations from the Mean

Next, calculate the deviations from the mean by subtracting the mean from each data point. Using the same example, the deviations would be (1 - 3), (2 - 3), (3 - 3), (4 - 3), (5 - 3) = -2, -1, 0, 1, 2.

3

Square the Deviations

Then, square each deviation. Using the same example, the squared deviations would be (-2)^2, (-1)^2, 0^2, 1^2, 2^2 = 4, 1, 0, 1, 4.

4

Calculate the Variance

After that, calculate the variance by summing up the squared deviations and dividing by the number of data points. Using the same example, the variance would be (4 + 1 + 0 + 1 + 4) / 5 = 10 / 5 = 2.

5

Calculate the Standard Deviation

Finally, calculate the standard deviation by taking the square root of the variance. Using the same example, the standard deviation would be sqrt(2) ≈ 1.41.

6

Interpret the Results

The standard deviation represents how spread out the values are from the mean. A low standard deviation means the values are close to the mean, while a high standard deviation means the values are spread out.

Introduction to Standard Deviation

Standard deviation is a measure of the amount of variation or dispersion of a set of values. It represents how spread out the values are from the mean. In this guide, we will walk you through the steps to calculate the standard deviation of a dataset manually.

What is Standard Deviation?

The standard deviation is the square root of the variance. The variance is the average of the squared differences from the mean.

Formula

The formula for variance is: [ \sigma^2 = rac{\sum(x_i - \mu)^2}{N} ] where ( \sigma^2 ) is the variance, ( x_i ) are the individual data points, ( \mu ) is the mean, and ( N ) is the number of data points.

The formula for standard deviation is: [ \sigma = \sqrt{ rac{\sum(x_i - \mu)^2}{N}} ]

Step-by-Step Guide

To calculate the standard deviation, follow these steps:

Prerequisites

Before starting, make sure you have a dataset and have calculated the mean of the dataset.

Steps

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