Outlier Calculator
Detect possible outliers with Tukey’s IQR fences, standard Z-scores, or robust modified Z-scores. Results update automatically as you edit the data or settings.
Separate values with commas, spaces, semicolons, or new lines. Scientific notation is supported.
| Position | Value | IQR | Modified Z | Z-score | Selected result |
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How this is calculated
Accuracy notes and verification tests
The IQR method uses lower and upper inner fences of Q1 − 1.5×IQR and Q3 + 1.5×IQR by default. Values beyond inner fences are potential outliers; the traditional outer fences use 3×IQR. The modified Z-score uses M = 0.6745(x − median)/MAD. Standard Z-scores use z = (x − mean)/SD.
Outlier rules are screening methods, not automatic instructions to delete data. Investigate data entry, measurement, study design, and domain context before excluding observations.
This Outlier Calculator helps researchers, students, and analysts identify unusual observations in a numerical dataset using the interquartile range (IQR), standard Z-score, and modified Z-score methods. Paste your data to instantly see potential outliers, quartiles, IQR fences, median absolute deviation, standardized scores, method agreement, and an interactive box-plot-style visualization. Because different outlier methods make different assumptions, the tool lets you compare results and inspect the exact formula values before deciding how an unusual observation should be handled in your analysis.
