Loona Scatter Plot Maker — Free Scatter Charts with Trend Line
Does more study mean better marks? Does price follow size? A scatter plot shows whether two things move together — and the trend line puts a slope on the relationship.
How to use the Scatter Plot Maker
- Type your labels and numbers into the grid, or paste CSV into the box below the chart and press Apply CSV.
- Adjust the title, legend and per-series colours until the chart reads clearly at a glance.
- Press Download chart as PNG and drop the image into your document, slides or post. Use Copy my data as CSV to save your figures for later.
How it works
Each row becomes one point: X from the first series, Y from the second; row labels name the points in your table. The axes auto-fit the data range. The trend line is the least-squares fit — the straight line that minimises the squared distances to all points. The chart is drawn by hand on an HTML canvas by Loona’s shared chart engine — no chart library and no server. Everything is computed locally, so your numbers never leave your device.
Worked example
A teacher plots study hours against test marks for eight students. The rising trend line makes the case for homework better than any speech.
Frequently Asked Questions
What do the two series mean?
Series 1 is the horizontal (X) value, Series 2 the vertical (Y) value, row by row. Labels name each row.
What is the trend line?
The least-squares best-fit straight line. Its slope shows how much Y changes, on average, when X rises by one.
Can I add more points?
Yes — Add row adds a point. Rows with a missing Y are skipped.
Does a trend prove cause?
No — scatter shows association, not causation. The how-it-works note on this page says the same; always think about other explanations.