Third Quartile Calculator
Enter numeric data to compute the third quartile (upper quartile) along with other summary statistics. Select the quartile method that matches your reference.
Q1: 15.7500
Median (Q2): 22.5000
Q3 (third quartile): 29.2500
Minimum: 12
Maximum: 33
Count: 8
How to Use This Calculator
- Enter the dataset values separated by spaces, commas, or line breaks.
- Select the inclusive or exclusive quartile method.
- Review the computed third quartile and other summary statistics.
- Apply Q3 to evaluate the upper tail of your data distribution.
Formula
Inclusive: Q3 = median of data at position 0.75 × (n + 1)
Exclusive: split data at median and take median of upper half
Linear interpolation handles fractional positions
Full Description
The third quartile (Q3) marks the value below which 75% of observations fall. The calculator supports both inclusive and exclusive definitions to match textbook conventions or statistical software implementations.
Frequently Asked Questions
Which quartile method should I choose?
Inclusive aligns with many textbooks; exclusive matches certain software (e.g., Excel). Use the method consistent with your assignment or analysis.
How many values do I need?
Quartiles can be computed for any dataset with at least one observation. Larger samples provide more stable quartile estimates.
Are decimals handled?
Yes. Input values can be integers or decimals; the calculator sorts numerically.
How does Q3 relate to IQR?
IQR = Q3 − Q1. Together, quartiles describe the middle spread of the data.