Upper and Lower Fence Calculator

Your details

Enter numbers separated by commas, spaces, or line breaks. At least 4 values are needed to compute quartiles.
Inner fences (1.5 x IQR) flag mild outliers and are used in standard boxplots. Outer fences (3 x IQR) flag extreme outliers only.
Lower fence1 mild outlier detected
-1.75

Q1 minus 1.5 x IQR. Values below this are mild outliers.

Upper fence22.25
Q1 (25th percentile)7.25
Q3 (75th percentile)13.25
IQR (interquartile range)6
Mild outlier count1
Mild outliers85.00
Median (Q2)9.5
Data points10
Q17.25
Median9.5
Q313.25
IQR6

1 mild outlier detected outside [-1.7500, 22.2500].

  • The interquartile range (IQR) is 6.0000, so the inner fences sit 9.0000 units beyond Q1 and Q3.
  • 1 value (10.0% of the data) lies beyond the inner fences and is classified as mild outliers.
  • 1 value also exceed the outer fences (3 x IQR) and is classified as extreme outliers.
  • Outliers are not always errors - they may reflect genuine variability, measurement differences, or interesting edge cases worth investigating.

Next stepReview the flagged value to determine whether they reflect data-entry errors, genuine extremes, or subgroup differences before deciding whether to exclude them.

 = Powered by OnlyCalculators