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Outlier Calculator

Identify statistical outliers in your dataset using the IQR (Interquartile Range) method. Find unusual values that fall outside the normal range of your data.

⚠️ You need at least 4 data points to calculate quartiles. Currently: points.

📊 Statistical Summary

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Data Points
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Q1 (25%)
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Median (Q2)
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Q3 (75%)
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IQR
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Lower Bound
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Upper Bound
0
Outliers Found

🎯 Detected Outliers

✅ No outliers detected in your dataset. All values fall within the normal range.

📈 Sorted Data (Outliers Highlighted)

💡 How to Use This Tool

Detect outliers in your dataset with just a few steps:

1

Enter Your Data

Input numbers separated by commas, spaces, or new lines.

2

View Statistics

See quartiles, IQR, and bounds calculated in real-time.

3

Identify Outliers

Outliers are highlighted and listed separately.

4

Copy Results

Copy the complete analysis to share or save.


📖 About Outlier Calculator

What is an Outlier?

An outlier is a data point that differs significantly from other observations in a dataset. Outliers can indicate measurement errors, data entry mistakes, or genuinely unusual values worth investigating.

The IQR Method

This calculator uses the Interquartile Range (IQR) method, a robust statistical technique for detecting outliers:

How It Works

  1. Sort the data in ascending order
  2. Find Q1 (25th percentile) - the median of the lower half
  3. Find Q3 (75th percentile) - the median of the upper half
  4. Calculate IQR = Q3 - Q1
  5. Lower Bound = Q1 - (1.5 × IQR)
  6. Upper Bound = Q3 + (1.5 × IQR)
  7. Values below the lower bound or above the upper bound are outliers

Common Use Cases

  • Data Cleaning: Identify erroneous entries before analysis
  • Quality Control: Detect defective products in manufacturing
  • Finance: Find unusual transactions or market anomalies
  • Research: Validate experimental data
  • Sports Analytics: Identify exceptional performances

Privacy & Security

All calculations happen locally in your browser using JavaScript. Your data never leaves your device - complete privacy guaranteed.


❓ Frequently Asked Questions

Yes! All calculations happen locally in your browser using JavaScript. Your data never leaves your device and is not sent to any server.
The IQR (Interquartile Range) method identifies outliers by calculating the range between the 25th percentile (Q1) and 75th percentile (Q3). Values falling below Q1 - 1.5×IQR or above Q3 + 1.5×IQR are considered outliers.
You need at least 4 data points to calculate quartiles and detect outliers. More data points will provide more reliable results.
Enter numbers separated by commas, spaces, or new lines. The calculator automatically parses your input and ignores any non-numeric characters.
Yes! This tool is completely free with no usage limits or hidden fees. No account or signup required.