Box Plot Generator
Upload a CSV or paste it directly to draw a box plot for one or more numeric columns, side by side on a shared axis. Each box shows the interquartile range and median; outliers are flagged with the standard 1.5×IQR Tukey fence and drawn as individual points rather than stretching the whisker to them. A table below the chart lists min/Q1/median/Q3/max/IQR/outlier count per column. Download as a PNG. Runs entirely client-side — nothing is uploaded.
| Column | Min | Q1 | Median | Q3 | Max | IQR | Outliers |
|---|---|---|---|---|---|---|---|
| team_a | 72.00 | 73.75 | 76.00 | 78.50 | 90.00 | 4.75 | 1 |
| team_b | 85.00 | 86.75 | 88.50 | 90.25 | 92.00 | 3.50 | 0 |
| team_c | 60.00 | 67.25 | 69.50 | 71.25 | 95.00 | 4.00 | 2 |
About this tool
This tool draws a box plot for one or more numeric columns, showing each column's distribution at a glance: the box spans the interquartile range (Q1 to Q3, the middle 50% of values), the line inside it marks the median, and the whiskers extend to the furthest values that aren't outliers. An outlier is flagged using the standard Tukey fence — any value more than 1.5× the IQR beyond Q1 or Q3 — and drawn as an individual point rather than stretching the whisker out to it, which is what actually makes a box plot useful for spotting anomalies at a glance. Selecting multiple columns draws them side by side on a shared Y axis, useful for comparing distributions directly (e.g. test scores across several groups). It runs entirely client-side — nothing you upload or paste is ever sent anywhere.
What you can do
- Box plots for one or several numeric columns side by side
- Median, quartiles, IQR, and Tukey-fence outliers, computed and listed per column
- Upload a .csv file, or paste CSV directly
- Download the chart as a PNG
- Nothing is uploaded — everything runs locally in your browser
How to use
Step 1
Add your CSV
Upload a .csv file, or paste it directly.
Step 2
Pick numeric columns
Every genuinely numeric column is selected by default — toggle any off, or select just one.
Step 3
Read the stats
The chart and the table below it both show median, quartiles, IQR, and outlier count per column.
Example
This CSV:
CSV
team_a,team_b 72,88 75,90 78,85 80,92 74,300
draws team_a and team_b as separate boxes side by side, with the 300 in team_b correctly flagged and drawn as an individual outlier point rather than dragging the whisker up to it.
How your data is handled
This tool is labeled 🟢 Browser: your CSV is parsed and the statistics are computed directly in your browser — nothing is uploaded to a server, and nothing about it is retained once you leave the page.
Frequently asked questions
What do the box and whiskers actually represent?+
The box spans the interquartile range (Q1 to Q3 — the middle 50% of values), with a line at the median. The whiskers extend to the furthest values that aren't flagged as outliers, so the whisker length reflects the actual spread of typical values, not the true min/max.
How is an outlier decided?+
The standard Tukey fence: any value more than 1.5× the interquartile range (IQR = Q3 − Q1) beyond Q1 or beyond Q3. This is the conventional definition used by most statistical software's default box plot.
What quartile method is used?+
Linear interpolation between ranks (the same method numpy's default and Excel's QUARTILE.INC use) — the convention most people expect from "the quartile" without further qualification.
Can I compare multiple columns at once?+
Yes — select more than one numeric column and each is drawn as its own box on a shared Y axis, useful for comparing distributions side by side (test scores across groups, response times across servers, and similar).
Is my CSV uploaded anywhere?+
No — whether uploaded as a file or pasted, your CSV is parsed and the statistics are computed directly in your browser. Nothing here ever leaves your device.