Calculate interquartile range (IQR), semi-IQR, midhinge, and coefficient of quartile deviation. Detect mild and extreme outliers using Tukey's fences with box plot visualization.
You might also find these calculators useful
Calculate the interquartile range (IQR) and related statistics for any dataset. Detect outliers, compute quartile deviation (semi-IQR), midhinge, and coefficient of quartile deviation with interactive box plot visualization.
The interquartile range (IQR) is a measure of statistical dispersion, representing the spread of the middle 50% of your data. Also called midspread, middle 50%, or H-spread, it's calculated as IQR = Q3 - Q1 (the difference between the 75th and 25th percentiles). IQR is robust to outliers, making it more reliable than range for skewed distributions.
IQR Formula
IQR = Q₃ - Q₁Identify unusual values in datasets using Tukey's fence method (1.5×IQR and 3×IQR rules).
IQR defines the box in box plots, showing the middle 50% of data distribution.
Evaluate data spread and identify potential errors or anomalies in measurements.
Compare variability across different groups or time periods using a robust measure.
Quartile deviation, also known as semi-interquartile range, equals half the IQR (IQR ÷ 2). It provides a measure of dispersion that shows the average distance of Q1 and Q3 from the median, useful for symmetric distributions.