How to Make a Box Plot (Box and Whisker) Online

To make a box plot, open the Box Plot Maker and paste your numbers: spreadsheet columns with the group names in the first row, or one group per line such as Class A: 62, 68, 71, 75. Each group becomes a box showing the median, quartiles and range. Choose Vertical or Horizontal, the whisker rule, and the quartile method, then download a PNG, JPG or SVG.

Make a box plot step by step

1. Open the Box Plot Maker.
2. Enter the data in the Data box, either:
   • Columns pasted from Excel or Google Sheets, group names in the first row, or
   • One group per line: Class A: 62, 68, 71, 75, 80. A single column of numbers makes one box.
3. Under Options, choose:
   • Orientation: Vertical or Horizontal.
   • Whiskers: 1.5 × IQR, outliers as dots or Minimum to maximum.
   • The Quartile method (see below).
   • Mark the mean (×), Show every data point, Solid boxes and One colour for all boxes.
4. Set the title and style, then download PNG, SVG or JPG.

Reading a box plot

Each box summarises a group with five numbers:

• Minimum and maximum — the ends of the whiskers (or the furthest points within the whisker limit).
• Q1 (first quartile) — a quarter of the values are below it; the bottom of the box.
• Median — the middle value; the line inside the box.
• Q3 (third quartile) — three quarters are below it; the top of the box.

The box holds the middle 50% of the data. The × marks the mean, so you can see how far skewed data pulls it away from the median. With 1.5 × IQR whiskers, points beyond 1.5 times the box height from the box are drawn as outlier circles.

Comparing groups

Box plots shine when comparing several groups side by side:

• Different medians — one class scored higher overall.
• Different box heights — one group is more consistent.
• Outliers — a few values far from the rest, worth checking.
• Skew — a median close to one end of the box, or a long whisker on one side.

Which quartile method?

Different calculators and spreadsheets compute quartiles differently, which can confuse students checking answers:

• Median of halves matches TI-84 calculators and most textbooks.
• Linear interpolation matches Excel's QUARTILE.INC and Google Sheets.

Choose the one your class or report uses, and the numbers will match.

Box plot or histogram?

A histogram shows the full shape of one group's distribution — peaks and gaps. A box plot compresses each group to five numbers, which makes comparing many groups at once much easier. Use both: a histogram to understand one group, box plots to compare several.

A worked example

Paste test scores for three classes in three columns. The boxes show at a glance that Class B has the highest median but also the widest spread, while Class C is the most consistent — insights that a table of averages alone would hide.

Show every data point

With few values per group, a box can hide how little data it's based on. Tick Show every data point to draw the individual values beside each box — readers then see both the summary and the raw data, and small groups can't pass for big ones.

Related charts

• The relationship between two measurements: the Scatter Plot Maker.
• Comparing averages or totals rather than spreads: the Bar Chart Maker.

Privacy

Your numbers stay in your browser — nothing is uploaded or stored.

Frequently asked questions

How many values does a group need?

At least five to make sense; twenty or more is better.

Why does my outlier not show as a dot?

Choose 1.5 × IQR, outliers as dots. With Minimum to maximum, whiskers reach the extremes and no points are marked.

Can groups have different numbers of values?

Yes — each column or line can be any length.