What this calculator does
Outlier fences (Tukey) works out the IQR-based cutoffs beyond which a data point counts as an outlier. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaLower fence = Q1 − 1.5×IQR; Upper fence = Q3 + 1.5×IQR (3×IQR for "far out" points)
The inputs explained
| Field | What to enter |
|---|---|
| Data (comma or space separated) | A list of numbers, separated by commas or spaces. |