How to use the Box Plot Maker
- 1. Enter the groupsType one group per line as Name: values.
- 2. Choose whiskersPick 1.5 × IQR to show outliers, or min to max.
- 3. Make and downloadCreate the chart and save it as PNG or SVG.
Reading a box plot
The box runs from Q1 (25th percentile) to Q3 (75th percentile), so it holds the middle half of the data. The thick line is the median. With Tukey whiskers, each whisker reaches the furthest value within 1.5 × IQR of the box, and anything beyond is drawn as a circle.
Worked example (default data): Batch A has Q1 = 70.25, median 74.5 and Q3 = 78.5, so IQR = 8.25 and the upper fence is 90.875. The score of 95 lies beyond it and is drawn as an outlier. Batch B's whole box sits lower (median 65.5), so batch A did better overall, and with similar spread.
When to use a box plot
- Comparing groups: salaries by department, delivery times by city, marks by batch.
- Spotting skew: a median close to one end of the box, or one long whisker, means a skewed distribution.
- Finding outliers before averaging or modelling.
- Compact summaries when a full histogram per group would take too much space.
A box plot hides the detailed shape. Two peaks inside one group will not show, so pair it with a histogram when in doubt. Quartiles use the inclusive method (Excel QUARTILE.INC); small samples can give slightly different boxes in other software that uses another method. To list outliers for one group only, use the outlier detector.
Frequently asked questions
Do I need group names?
No. Leave out the name and colon for a single group; it will be labelled Group 1.
How many values per group?
At least 4. Box plots are most useful with 10 or more values per group.
Is the Box Plot Maker free?
Yes, the Box Plot Maker is free. The first time you make your first box plot, you are asked for your name and WhatsApp number once. After that, this and every other Uncodemy tool opens straight away without the form.