Outlier Calculator

Find the outlier fences using the 1.5×IQR rule.

Value 1

Value 2

Value 3

Value 4

Value 5

Lower fence -4

Upper fence 28

IQR 8

Formula: fences = Q1 − 1.5·IQR and Q3 + 1.5·IQR

Step-by-step with your numbers:

1. Values used:

2. Value 1 = 4

3. Value 2 = 8

4. Value 3 = 15

5. Value 4 = 16

6. Value 5 = 23

8. Lower fence = Value 1 - Value 2 = 4 - 8 = -4

9. Upper fence = 28

10. IQR = 8

Did we solve your problem today?

Values outside the fences are flagged as potential outliers.

The math behind it

lower fence = Q1 − 1.5×IQR; upper fence = Q3 + 1.5×IQR. Anything beyond is an outlier.

4,8,15,16,23 → fences −4 and 28.

Why 1.5?

It's the standard Tukey rule for mild outliers (3× for extreme).