Quartile Calculator
Split a dataset of up to 8 numbers into quarters and find Q1, the median (Q2) or Q3 using linear interpolation.
Only the first this-many values below are included.
Your results
Calculation breakdown
- Quartile
- Qk = percentile at k × 25%, using linear interpolation
Worked example
For the dataset 41, 47, 52, 55, 58, 63, 66, 70, Q1 sits near 51, the median (Q2) near 56.5 and Q3 near 64.75, splitting the sorted data into four equal-sized groups.
Assumptions
- Uses linear interpolation between sorted values, the same convention used by most spreadsheets.
- Quartiles become less meaningful with very small datasets.
How this calculator works
Enter up to 8 numeric values and choose Q1, Q2 (the median) or Q3. The calculator sorts the data and finds the requested quartile using linear interpolation, along with all three quartiles for comparison.
Frequently asked questions
What is Q2?
Q2 is the median — the middle value of the sorted dataset, with half the values above it and half below.
How are quartiles used in a box plot?
Box plots use Q1, Q2 and Q3 to draw the box, showing the middle 50% of the data and the median line inside it.
Do I need a lot of data for meaningful quartiles?
Quartiles are more meaningful with larger datasets; with only a few values they are a rough approximation.