Math & StatisticsFormula-based · Runs in your browser

Quartile Calculator

Calculate quartiles, the interquartile range, fences, and five-number summary.

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Inputs

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Result

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Calculated locally
Median Q2
First quartile Q1
Third quartile Q3
Interquartile range
Lower outlier fence
Upper outlier fence

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Calculation steps

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  1. 1

    Formula selected

    The calculator uses the following formula or method.

    IQR = Q3 − Q1; Tukey fences = Q1 − 1.5IQR and Q3 + 1.5IQR

  2. 2

    Values entered

    Your values are placed into the calculation.

    Enter values to see what is used in this step.

  3. 3

    Result calculated

    The formula or method produces the following result values.

    Results will appear after a successful calculation.

  4. 4

    Answer formatted

    Displayed values are rounded and formatted using each output’s configured precision.

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What this calculator does

Calculate quartiles, the interquartile range, fences, and five-number summary.

How it works

The calculator evaluates IQR = Q3 − Q1; Tukey fences = Q1 − 1.5IQR and Q3 + 1.5IQR. Inputs are checked before calculation, and invalid values such as zero denominators or out-of-range selections produce a clear error instead of a misleading result.

Input query strings and outputs

Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.

Input query strings

1
  • ?data= Data values (comma or space separated)

    Text · Required · Default: 4, 7, 7, 9, 12, 15, 18, 21

Outputs

6
  • q1 First quartile Q1

    Number

  • q2 Median Q2

    Number · Primary output

  • q3 Third quartile Q3

    Number

  • iqr Interquartile range

    Number

  • lowerFence Lower outlier fence

    Number

  • upperFence Upper outlier fence

    Number

Inputs and results

The inputs are Data values (comma or space separated). Results include First quartile Q1, Median Q2, Third quartile Q3, Interquartile range, Lower outlier fence, Upper outlier fence.

Sources
  • No external reference is listed for this calculator. Its formula and variable definitions are shown above.
Limitations
  • Results depend on the selected method and input assumptions. Displayed decimals may be rounded; retain appropriate precision for later calculations.