Standard Deviation Calculator

Summary

Enter a list of numbers to instantly calculate mean, variance, and both population and sample standard deviations.

How it works

1. Enter your numbers separated by commas, spaces, or new lines.
2. The calculator parses and validates each value in real time.
3. Mean is computed as the sum of all values divided by count.
4. Variance is the average of squared deviations from the mean.
5. Population SD divides by N; sample SD divides by N-1 (Bessel's correction).
6. Results update instantly as you type.

Use cases

• Analyze test scores or survey results in statistics class.
• Measure data spread in scientific experiments.
• Evaluate consistency in quality control and manufacturing.
• Assess investment return volatility in finance.
• Compare variability across multiple data sets.
• Prepare descriptive statistics for a research paper.

Frequently Asked Questions