Outlier Detector
Flag outliers with the 1.5 IQR rule.
Spot the odd values out
Outliers can distort averages and mislead analysis, so flagging them matters. The interquartile-range rule is the standard robust method: it fences off values far from the central half of the data.
In a tidy set with a stray 90, the tool computes the fences from the quartiles and flags the 90 as an outlier. Because it uses the IQR, the extreme value does not move the thresholds.
Robust and private
The calculation runs in your browser, so your data is never uploaded.
Frequently Asked Questions
How are outliers found?
By the interquartile-range rule: values below Q1 minus 1.5 times the IQR, or above Q3 plus 1.5 times the IQR, are flagged.
Why the IQR method?
Because it is robust — it uses the middle half of the data, so the outliers themselves do not distort the thresholds.
What does it return?
The lower and upper fences and any values that fall outside them.
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