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Calculate the population standard deviation of a number list instantly and review the variance, mean, count, and sum.
Calculate standard deviation from a list of numbers
Enter a list of numbers to calculate population standard deviation, variance, mean, and count in one focused result card.
Measure how spread out a dataset is around its mean
Use this standard deviation calculator when you want to measure variability in a number list. It is useful for grades, experiments, datasets, prices, analytics, and quick statistics checks where the main question is how far the values tend to sit from the average.
Enter a list of numbers to calculate standard deviation instantly.
Standard deviation result
Review the standard deviation first, then compare the variance, mean, count, and sum from the current dataset.
Live result
Enter numbers to calculate standard deviation.
The population standard deviation will appear here as soon as the input is valid.
How to use the standard deviation calculator
- Enter or paste the numbers you want to evaluate.
- Separate values with commas, spaces, or new lines.
- Review the main result to see the population standard deviation instantly.
- Use the supporting values to compare the variance, mean, count, and sum.
- Use Example to load a sample dataset or Clear to reset the calculator.
Standard deviation calculator examples
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What is the standard deviation of 12, 15, 18, 21, and 24?
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Calculate standard deviation from a list of grades
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Find the standard deviation of a small dataset
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How do you calculate standard deviation from multiple values?
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Calculate variability around the mean for a number list
What this standard deviation calculator shows
This tool calculates the population standard deviation for a list of numbers and also shows the related variance, mean, count, and sum. Standard deviation measures how far the values tend to sit from the mean, so it helps you understand whether a dataset is tightly grouped or more spread out.
When standard deviation is useful
A standard deviation calculator is useful for grades, experiments, finance examples, survey results, analytics, and any dataset where you want a quick measure of spread. Instead of calculating deviations from the mean and squaring them by hand, you can paste the values and review the result instantly.
Standard deviation vs variance
Variance is the average squared distance from the mean, while standard deviation is the square root of that variance. They describe the same spread from different angles, but standard deviation is often easier to interpret because it stays in the same unit as the original values.
Standard deviation calculator FAQs
What formula does this standard deviation calculator use?
This tool uses the population standard deviation formula. It calculates the mean, finds each squared distance from that mean, averages those squared distances to get the variance, and then takes the square root.
Does this tool use population or sample standard deviation?
It uses population standard deviation for the current dataset, so the variance is divided by the total count of values.
Can I use decimals and negative numbers?
Yes. The calculator accepts valid numeric inputs including decimals and negative values.
What happens if one of the values is not a valid number?
The tool shows a clear validation message and asks you to fix the invalid value instead of returning a partial result.