StratumBox plot maker
Paste your numbers and get a clean box-and-whisker plot in seconds — median, quartiles, whiskers, and outliers drawn automatically. Compare groups side by side, then download as PNG or SVG. Everything runs in your browser; nothing is uploaded.
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That is one chart from one column. Stratum draws it from a whole CSV — box and violin plots, the t-tests and ANOVA behind the groups, and click any outlier to see the row it came from.
Try Stratum freeHow to use it
- One group: paste a single column of numbers (one per line).
- Compare groups: paste several columns with a header row — each header becomes a box label. Copy-paste straight from Excel or Google Sheets (tab-separated) works.
- Long format also works: two columns of
group, valuerows are grouped automatically.
How the box is drawn. The box spans the first quartile (Q1) to the third (Q3); the line inside is the median. Whiskers reach the most extreme points still within 1.5 × IQR of the box (the Tukey rule), and anything past that is plotted as an outlier. Quartiles use linear interpolation (type 7) — the same definition as NumPy, pandas, and R, documented in Stratum's conventions.
New to reading these? See Box plots explained: quartiles, IQR & outliers and the quartiles & IQR glossary entry.
Need more than a picture? This maker draws one chart from numbers you paste. Stratum does the rest of the job: load a whole CSV, get box plots and violin plots, run the t-tests and ANOVA behind the groups, spot-click an outlier to reveal its row, and export every chart to PNG, PDF, TIFF, or JPEG. See how it works on a Mac → or download Stratum.
See also
- Practice data
- Free sample datasets to paste in
- Learn
- Quartiles & IQR · How to read a box plot
- More tools
- Statistics calculators · All free resources