Your files never leave your device. All processing happens in your browser.
Upload a chart image to the Img Stop Plot Digitizer. Click two known points on the X axis and two on the Y axis and type their values. Then click on the data to add points, or pick the line colour and click Find data points to trace it automatically. Copy the table as CSV or TSV, or download CSV and JSON.
About the Plot Digitizer (Graph to Data)
The Img Stop Plot Digitizer gets the numbers back from a chart when you only have a picture of it – from a paper, a datasheet, a scanned book or a screenshot. It works with line charts, scatter plots and curves, with linear or logarithmic axes, and even with slightly rotated scans.
After calibrating the axes you can place points by hand with a zoom loupe for precision, drag them to fine-tune and delete them, or let the tool find a line or the markers of one colour for you. Several datasets with their own colours can be collected from one chart. Your image stays on your device.
Key features
- Axis calibrationTwo points on each axis, linear or logarithmic, also for rotated or skewed scans.
- Precise clickingA zoom loupe, zoom and pan, drag to move points, arrow keys to nudge them.
- Automatic extractionPick the colour of a line or markers and get the points in one click.
- Several datasetsCollect many curves from one chart, each with its own name and colour.
- Editable tableValues sorted by X; type a new value to move a point exactly.
- Easy exportCopy CSV or TSV for Excel and Google Sheets, or download CSV and JSON.
How to use the Plot Digitizer (Graph to Data)
- Upload the chart Drop a PNG or JPG image of the graph, or paste a screenshot.
- Calibrate the axes Click X1, X2, Y1 and Y2 on known axis values and type those values.
- Add the data Click on the data points, or use Auto: pick the line colour and click Find data points.
- Export Copy the values as CSV or TSV, or download a CSV or JSON file.
Plot Digitizer (Graph to Data) at a glance
| Price | Free |
|---|---|
| Input | PNG, JPG, WebP, screenshot |
| Axes | Linear and logarithmic |
| Modes | Manual points, auto line, auto markers |
| Export | CSV, TSV, JSON |
| Privacy | Works in your browser – no upload |
When to use it
- Recover data from a figure in a scientific paper when the raw data is not published.
- Read values from a curve in a datasheet, such as a sensor or battery curve.
- Compare your own measurements with a published graph.
- Turn an old printed chart into numbers for a spreadsheet.
- Get the points of a scatter plot to recalculate a trend line.
Tips for the best result
- Use calibration points far apart, near the ends of each axis, for the best accuracy.
- Zoom in (Ctrl + scroll or pinch) and use the loupe to click exactly on axis ticks.
- For Auto, draw a search box around the plot area so the axes and labels are ignored.
- If Auto misses parts of a line, raise the tolerance a little; if it picks up other things, lower it.
Frequently asked questions
How do I extract data from a graph image?
Upload the image, click two known points on each axis and type their values. Then click on the data points or use automatic extraction by colour. The table shows the real X and Y values, ready to copy as CSV.
Does it work with logarithmic axes?
Yes. Tick "X axis is logarithmic" or "Y axis is logarithmic" and the values are calculated on a log scale. Log values must be above zero.
Can it trace a line automatically?
Yes. Choose Auto, pick the colour of the line from the chart and click Find data points. The tool samples the line along the X axis every few pixels. For scatter plots choose "Dots / markers" to find the centre of every marker.
What if the scan is a little rotated?
The calibration uses all four points, so a slightly rotated or skewed scan is handled correctly as long as the axis points are placed on the axes.
How accurate is it?
Accuracy depends on the image resolution and line width. On a clear chart the error is usually below one pixel, often under 0.5 % of the axis range.
Is my image uploaded?
No. The chart is processed in your browser and never leaves your device.
Learn more
- MDN: Image file types – common image formats explained
Made and maintained by the Img Stop team.