Finds all three quartiles of a dataset — the values that split it into four equal-sized groups.
How it works
Q2 is the overall median; Q1 is the median of the lower half of the sorted data, and Q3 is the median of the upper half.
What this does not include
This does not include the interquartile range itself — for that single spread measure, use this site’s IQR calculator instead.
How to use this calculator
- Enter your dataset as comma-separated numbers.
A worked example
Dataset 1 through 9 (odd count): Q1 = 2.5, Q2 (the median) = 5, Q3 = 7.5.
Dataset 2, 4, 4, 4, 5, 5, 7, 9 (even count): Q1 = 4, Q2 = 4.5, Q3 = 6.
What the terms mean
| Term | Meaning |
|---|---|
| Q1 | 25th percentile — median of the lower half |
| Q2 | 50th percentile — the overall median |
| Q3 | 75th percentile — median of the upper half |
Edge cases worth knowing
With an odd-length dataset, the overall median is excluded from both halves before finding Q1 and Q3 — the exclusive method used here, the most commonly taught convention.
The three quartiles split the data into four equal-sized groups, each holding roughly a quarter of the values.
Frequently asked questions
What does Q1 represent?
The 25th percentile — a quarter of the data falls below it.
Is Q2 the same as the median?
Yes — Q2 is just another name for the overall median, the point that splits the data exactly in half.
Why use the “exclusive” median method?
It’s the most commonly taught convention for computing quartiles, excluding the overall median itself from both halves when the dataset has an odd length.
