Quick guide
How to use this calculator
- Enter the observations, probabilities, model parameters, or summary statistics requested by the visible labels.
- Keep every value on the same scale and confirm that the selected sampling relationship, distribution, and tail convention match the question you are investigating.
- Read the result together with its assumptions and interpretation. Statistical output summarizes uncertainty under a model; it does not repair biased data or establish causation.
Calculation method
How the interquartile range calculator works
IQR = Q3 − Q1; fences = Q1 − 1.5×IQR and Q3 + 1.5×IQR.
IQR is resistant to extreme values and is especially useful for skewed data.
Worked example
Interquartile Range example
If Q1=12 and Q3=20, IQR=8 and the fences are 0 and 32.
IQR = Q3 − Q1; fences = Q1 − 1.5×IQR and Q3 + 1.5×IQR.
Supported inputs
Precision and limits
Model and design
Fence exceedance is a screening rule, not proof that an observation is erroneous.
Numerical scope
Inputs use double-precision numerical methods with guarded domains. Datasets accept up to 10,000 finite plain-decimal values. Extremely large parameters or probabilities deep in a numerical tail may require specialist statistical software.
Interpretation
IQR is resistant to extreme values and is especially useful for skewed data.
Decision boundary
The calculator does not validate how data were collected, diagnose dependence or bias, choose a scientifically meaningful effect, or replace review by a qualified statistician for consequential research, medical, regulatory, safety, or policy decisions.
Privacy
Entered values and calculated results stay in this browser and are not sent to an analytics service.
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