Outlier Calculator
Identify values outside the 1.5 IQR Tukey fences using the stated quartile convention.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Numbers | Separate values with commas, spaces or line breaks. Use dots for decimals; at most 10,000 values. |
Understanding your result
These are descriptive results for the observations you entered, not proof of causation, significance or a particular population distribution.
Common mistakes
- Comparing different quartile/percentile conventions, or treating an outlier fence as proof that data is wrong.
Check your calculation
- Try a small hand-checkable list; confirm the stated quartile/rank/denominator convention before comparing with another application.
Calculation checks, sources and review limits
Which values fall outside the 1.5 IQR Tukey fences?
Identify values outside the 1.5 IQR Tukey fences using the stated quartile convention.
Common uses
- Identify values outside the 1.5 IQR Tukey fences using the stated quartile convention.
How it works
Flag x<Q1-1.5*IQR or x>Q3+1.5*IQR, type7 quartiles. Lists accept commas, semicolons, spaces or line breaks as separators; use a dot for decimals. At most 10,000 observations are supported. Calculations use floating-point arithmetic; displayed numeric results have up to 12 significant digits. Quantiles use linear interpolation with h=(n-1)p (Hyndman–Fan type 7). Other conventions can give different values.
Worked example
Enter Numbers: 1, 2, 3, 4, 100. The result is Outliers: 100; Lower fence: -1; Upper fence: 7.
FAQ
Which values fall outside the 1.5 IQR Tukey fences?
Flag x<Q1-1.5*IQR or x>Q3+1.5*IQR, type7 quartiles. Lists accept commas, semicolons, spaces or line breaks as separators; use a dot for decimals. At most 10,000 observations are supported. Calculations use floating-point arithmetic; displayed numeric results have up to 12 significant digits. Quantiles use linear interpolation with h=(n-1)p (Hyndman–Fan type 7). Other conventions can give different values.
What assumptions and limits apply?
Tukey fence is a descriptive rule, not proof of bad data or a significance test.