Five Number Summary Calculator
Enter a list of numbers to get its five-number summary (minimum, first quartile, median, third quartile and maximum), plus the IQR, range and outlier fences. A box-and-whisker plot is drawn for you, and you can switch quartile methods to match your textbook or software.
Separate numbers with commas, spaces or new lines.
Different textbooks, calculators and spreadsheets compute Q1 and Q3 differently; the table below compares them.
How to use the Five Number Summary Calculator
- Enter your data, separated by commas, spaces or new lines.
- Pick a quartile method if your class or software uses a specific one (the default matches the TI-84 and most textbooks).
- Read the five numbers, the IQR and the fences.
- Look at the box plot to see the spread and any outliers.
- Compare methods in the table if your answer differs from a book or spreadsheet.
How the five numbers are found
| Statistic | Definition | Example: 2, 4, 4, 5, 6, 7, 8, 9, 10, 12, 30 |
|---|---|---|
| Minimum | Smallest value | 2 |
| Q1 | Median of the lower half | Lower half 2, 4, 4, 5, 6 → 4 |
| Median | Middle of the sorted data | 6th value → 7 |
| Q3 | Median of the upper half | Upper half 8, 9, 10, 12, 30 → 10 |
| Maximum | Largest value | 30 |
| IQR | Q3 − Q1 | 10 − 4 = 6 |
| Fences | Q1 − 1.5·IQR, Q3 + 1.5·IQR | −5 and 19 → 30 is an outlier |
The example uses the exclusive method (the median is left out of both halves because n is odd), which is what the TI-84 and most introductory textbooks use.
Quartile methods compared
| Method | Q1 rule | Used by |
|---|---|---|
| Exclusive halves | Median of the values below the median | TI-83/84, many textbooks |
| Inclusive halves (Tukey hinges) | Median of the lower half including the median when n is odd | Tukey's original box plot, R fivenum() |
| QUARTILE.INC (type 7) | Interpolate at position (n − 1) × 0.25 + 1 | Excel QUARTILE / QUARTILE.INC, Google Sheets, R quantile() default, NumPy default |
| QUARTILE.EXC (type 6) | Interpolate at position (n + 1) × 0.25 | Excel QUARTILE.EXC, Minitab, SPSS |
Frequently asked questions
What is the five-number summary?
It is five values that describe a data set: the minimum, the first quartile Q1 (25th percentile), the median, the third quartile Q3 (75th percentile) and the maximum. Together they show the center, the spread and the range of the data, and they are what a box plot draws.
How do I find the five-number summary by hand?
Sort the data. The smallest and largest values are the minimum and maximum. The median is the middle value (or the average of the two middle values). Q1 is the median of the lower half of the data and Q3 the median of the upper half.
Why do different calculators give different quartiles?
There is no single agreed definition. The TI-84 and many textbooks exclude the median from the halves when n is odd; Tukey's hinges include it; Excel's QUARTILE.INC and QUARTILE.EXC interpolate between values using different positions. For large data sets the methods agree closely; for small ones they can differ.
What is the interquartile range (IQR)?
The IQR is Q3 − Q1, the spread of the middle 50% of the data. Unlike the range it is not affected by extreme values, so it is a robust measure of spread and is used to define outlier fences.
How are outliers shown in a box plot?
A common rule marks values below Q1 − 1.5 × IQR or above Q3 + 1.5 × IQR as outliers. The whiskers then stop at the most extreme values inside these fences, and the outliers are drawn as separate points.
Is the median the same as the mean?
Not usually. The median is the middle value of the sorted data; the mean is the sum divided by the count. In skewed data, or data with outliers, the mean is pulled toward the long tail while the median is not.