How to use this calculator
The calculator uses the median-of-halves convention for quartiles.
The method
IQR = Q3 − Q1
Enter your values in the labeled fields and choose Calculate. The result panel shows the answer and supporting values when useful.
WORKED EXAMPLE INPUT
Values: 1, 3, 4, 6, 8, 9, 12, 15
Select Calculate to evaluate these example values.
Scope and limitations
Quartile conventions vary; this page states and uses the median-of-halves method.
Common questions
Can I change the example values?
Yes. Replace every prefilled value with your own inputs and calculate again.
Are displayed results exact?
Some results are rounded for readability. Keep extra precision when the next step depends on the result.
Methods & verification
Formulas use standard mathematical definitions and fixed unit factors where applicable. See our methodology for numerical conventions, rounding, privacy, and limitations.