Standard Deviation Calculator
Compute mean, median, variance, and standard deviation from a set of numbers.
Paste or type a set of numbers separated by commas, spaces, or new lines, and this calculator returns the count, sum, mean, median, mode, min, max, range, plus population and sample variance and standard deviation. Everything runs locally in your browser, which is handy for homework, reports, and quick data checks.
Tool area
Who should use Standard Deviation Calculator
Useful for teachers, students, and researchers who need a quick summary of central tendency and spread.
This page is designed for quick checking and preparation, not for replacing official rules, institutional requirements, or professional software. When using Standard Deviation Calculator, test a small sample first so units, weights, page ranges, and output settings match your real task before processing the full dataset or document.
Method, interpretation, and limits
The tool reports both population and sample values. Use population SD for the complete group and sample SD for a sample drawn from a larger population.
Read the result together with the source data, sample size, page range, output format, or workflow rule. For applications, exams, reports, submissions, or public documents, treat the output as a draft check and verify it against the original source and official instructions.
- Do not mix units or nonnumeric text.
- Very small samples produce unstable SD estimates.
- SD alone does not prove normality.
Practical examples
These examples illustrate workflow ideas only. They are not official policy for any school, agency, exam board, or platform.
- A teacher checks whether class quiz scores are widely spread.
- A graduate student reviews pre-test data for outliers.
- A club summarizes satisfaction scores and checks agreement.
Related workflow
Pair with Z Score, T Score, and Grade Average tools for education-statistics workflows.
How to use
- Paste or type numbers, separated by commas, spaces, or new lines.
- Anything that is not a valid number is ignored automatically.
- Results update instantly, including mean, median, and standard deviation.
- Copy the full summary when you need it.
Use cases
- Find the mean and standard deviation of a set of exam scores.
- Check how spread out experimental or measurement data is.
- Compare population versus sample standard deviation.
Real examples
Example 1
A teacher checks whether class quiz scores are widely spread.
Example 2
A graduate student reviews pre-test data for outliers.
Example 3
A club summarizes satisfaction scores and checks agreement.
Good to know
- Do not mix units or nonnumeric text.
- Very small samples produce unstable SD estimates.
- SD alone does not prove normality.
FAQ
- Is Standard Deviation Calculator free to use?
- Yes. You can use the tool directly in the browser with no registration.
- Is my data uploaded?
- No. This tool runs locally in your browser and does not actively upload inputs or files to FreeTools servers.
- Can I treat the result as official?
- No. Use it as a calculation, cleanup, or checking aid and confirm formal requirements with official sources.
- What should I check when the result looks wrong?
- Review units, weights, page ranges, sample size, source format, whitespace, and output settings, then test again with a small known example.
- Which related tools should I use next?
- Pair with Z Score, T Score, and Grade Average tools for education-statistics workflows.
Privacy & local processing
🔒 This tool runs entirely in your browser. No data is uploaded to any server.
All statistics run locally in your browser; the numbers you enter are not uploaded.
Trust & usage note
This tool runs mainly in your browser. Your input is not actively uploaded to a server. Avoid entering highly sensitive data. Results are for reference only.
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