Interquartile range calculator

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Calculate interquartile range online with ease

Calculate the interquartile range (IQR) to measure statistical dispersion and identify outliers in your dataset. The IQR is a robust measure of spread that's resistant to extreme values.

Analyze csv, parquet, tsv and json in seconds

Calculate IQR instantly

Get quartiles (Q1, Q2, Q3)

Identify potential outliers

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Perfect for data analysis and outlier detection

How to calculate interquartile range (IQR) online

  1. Upload your data
    Use the input box at the top of the page to upload your dataset
  2. Select column
    Choose the numerical column you want to analyze
  3. View results
    See the IQR, quartiles, and outlier information instantly
  4. Analyze distribution
    Use the visualization to understand your data's spread and identify outliers

IQR calculation examples with different distributions

Normal distribution

A normal distribution typically shows a consistent IQR with few outliers. Outliers are identified using the 1.5 × IQR rule:

How outliers are calculated:

  • Lower fence = Q1 - 1.5 × IQR
  • Upper fence = Q3 + 1.5 × IQR
  • Any values below the lower fence or above the upper fence are considered outliers

Statistics:

  • IQR: 1.3648
  • Q1: 9.3200
  • Q3: 10.6848
  • Median: 10.0061
  • Number of outliers: 5
  • Lower fence: 7.2729
  • Upper fence: 12.7320

Skewed distribution

A right-skewed distribution often shows more potential outliers in the right tail. The 1.5 × IQR rule provides an objective method for identifying these extreme values, regardless of the distribution's shape.

Statistics:

  • IQR: 0.6919
  • Q1: 0.7196
  • Q3: 1.4115
  • Median: 1.0081
  • Number of outliers: 32
  • Lower fence: -0.3183
  • Upper fence: 2.4494

Bimodal distribution

A bimodal distribution demonstrates how IQR and outlier detection work with multi-peaked data. The same 1.5 × IQR rule applies, though interpretation may need more context due to the natural separation of peaks.

Statistics:

  • IQR: 10.0173
  • Q1: 4.9851
  • Q3: 15.0024
  • Median: 6.2626
  • Number of outliers: 0
  • Lower fence: -10.0408
  • Upper fence: 30.0283
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