Everyday Tools

Standard Deviation Calculator

Calculate standard deviation, variance, and mean from a comma-separated list of numbers.

Updated April 12, 2026
Free online tool
Planning and research use

Why this page exists

A number list becomes easier to interpret when spread and average are visible together instead of left to guesswork. This calculator helps visitors calculate standard deviation, variance, mean, and value count from a comma-separated list of numbers with a population or sample option.

Interactive tool

Run the estimate

Enter your numbers and read the result first, then use the sections below to understand what affects the outcome.

Calculator

Standard deviation calculator

Estimate standard deviation and variance from a comma-separated list of numbers.

Result

3.8262

Estimated standard deviation based on the valid numeric values found in the list entered, using the population or sample method selected.

Standard deviation3.8262

Variance14.6400

Mean9.4000

Count of values5

5 valid values produced a mean of 9.4000 in this population calculation.
Using the population method, the variance comes to about 14.6400 and the standard deviation comes to about 3.8262.
All comma-separated entries were read successfully as numeric values.

This is a simple descriptive-statistics calculator. Make sure the list contains only the values you want included, and choose population or sample mode based on how the list should be interpreted.

Planning note

Last updated April 12, 2026. Use this tool to compare scenarios and plan ahead, then confirm important details with the lender, employer, insurer, contractor, or other qualified provider involved in the final decision.

How it works

What the calculator is doing

Enter a comma-separated list of numbers and choose population or sample mode.

The calculator reads valid numeric entries, skips invalid ones, and calculates the mean.

It then calculates variance and standard deviation using the selected method.

Understanding your result

This is a simple descriptive-statistics calculator. The result depends on the values entered and on whether the list should be treated as a full population or as a sample.

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Examples

Ways people use this tool

Example scenarios help turn a quick estimate into a more useful comparison or planning step.

Measure spread in a small set of scores

Standard deviation can make it easier to see whether values are tightly clustered or spread out.

Switch between sample and population views

Changing the mode shows how the result differs depending on how the data set is interpreted.

Pair average and variation in one result

Seeing mean and standard deviation together often gives a clearer summary than the average alone.

FAQ

Common questions

What is the difference between population and sample mode?

Population mode divides by the total number of valid values, while sample mode divides by one less than that count to estimate variation from a sample.

Why are invalid entries skipped?

The calculator only includes values it can read as numbers, so text or malformed entries are ignored and noted in the result.

Why do I need at least two values for sample mode?

Sample standard deviation needs at least two valid values because the divisor becomes count minus one.

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Keep comparing

Use these related tools to compare nearby scenarios, check a second estimate, or keep narrowing down the right decision.

Everyday ToolsUpdated April 12, 2026