Statistical Calculators

Descriptive Statistics Calculator

Free online descriptive statistics calculator. Compute mean, median, mode, standard deviation, variance, quartiles, skewness, and more from your data.

Accepts numbers separated by commas, spaces, tabs, or new lines

How to Use the Descriptive Statistics Calculator

Enter your data values separated by commas, spaces, or new lines. The calculator computes all major descriptive statistics instantly.


Statistics Calculated

Measures of Central Tendency

StatisticDescription
MeanArithmetic average of all values
MedianMiddle value when data is sorted
ModeMost frequently occurring value(s)

Measures of Dispersion

StatisticDescription
Standard DeviationAverage distance from the mean
VarianceSquare of standard deviation
RangeMaximum minus minimum
IQRInterquartile range (Q3 - Q1)
CVCoefficient of variation (relative spread)

Distribution Shape

StatisticDescription
SkewnessMeasure of asymmetry
KurtosisMeasure of tail heaviness

Understanding the Results

Mean vs. Median

  • If mean ≈ median: Data is approximately symmetric
  • If mean > median: Data is right-skewed (pulled by high values)
  • If mean < median: Data is left-skewed (pulled by low values)

Standard Deviation

  • Low SD: Data points cluster closely around the mean
  • High SD: Data points spread widely from the mean

The 68-95-99.7 rule for normal distributions:

  • ~68% of data falls within 1 SD of the mean
  • ~95% of data falls within 2 SDs of the mean
  • ~99.7% of data falls within 3 SDs of the mean

Skewness Interpretation

ValueInterpretation
≈ 0Symmetric
> 0Right-skewed (positive skew)
< 0Left-skewed (negative skew)
|skew| < 0.5Approximately symmetric
|skew| > 1Highly skewed

Kurtosis Interpretation

ValueInterpretation
≈ 0Normal (mesokurtic)
> 0Heavy tails (leptokurtic)
< 0Light tails (platykurtic)

Population vs. Sample Statistics

This calculator provides both:

TypeStandard DeviationVarianceWhen to Use
Populationσ = √(Σ(x-μ)²/N)σ²When data is the entire population
Samples = √(Σ(x-x̄)²/(n-1))When data is a sample (most common)

The sample statistics use (n-1) in the denominator (Bessel’s correction) to provide an unbiased estimate.


The Five-Number Summary

The five-number summary provides a quick overview of data distribution:

  1. Minimum: Smallest value
  2. Q1 (25th percentile): 25% of data falls below
  3. Median (50th percentile): Middle value
  4. Q3 (75th percentile): 75% of data falls below
  5. Maximum: Largest value

This summary is the basis for box plots (box-and-whisker diagrams).


Detecting Outliers

Using the IQR method:

  • Lower fence: Q1 - 1.5 × IQR
  • Upper fence: Q3 + 1.5 × IQR

Values beyond these fences are potential outliers.


Example Interpretation

For the sample data: 12, 15, 18, 22, 25, 28, 30, 35, 38, 42, 45, 48, 52, 55, 60

StatisticValueInterpretation
Mean35.0Center of data
Median35.0Mean ≈ Median suggests symmetry
Std Dev15.2Moderate spread
Skewness0.0Symmetric distribution
IQR27Middle 50% spans 27 units

When to Use Different Measures

Use Mean when:

  • Data is symmetric
  • No extreme outliers
  • Interval or ratio scale

Use Median when:

  • Data is skewed
  • Outliers are present
  • Ordinal scale acceptable

Use Mode when:

  • Finding most common category
  • Nominal scale data
  • Describing typical case

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