Free · No account · Runs in browser

Extract data from any plot or chart in seconds

PlotExtract is a free plot digitizer and image measurement tool. Open an image, calibrate the axes, click your data points, and export them to CSV.

Launch PlotExtract
No sign-up. No upload. Works entirely in your browser.
PlotExtract plot digitizer showing a scatter plot being digitized with multiple data series

How to digitize a graph in 3 steps

1

Open your image

Drag and drop, click Open image, or paste with Ctrl+V.
2

Calibrate the axes

Click two known points on each axis and enter their values.
3

Click your data points

Click every point on the plot. Export to CSV when done.

Measure distances and angles on any image

PlotExtract also works as a precision image measurement tool. Use it on technical drawings, microscopy images, maps, or any photo with a scale reference.

Set a real-world scale

Mark two points of a known distance and enter the value. PlotExtract converts every subsequent measurement into your chosen unit.

Measure distance on any image

Click point A then point B. Get the pixel distance, the scaled real-world distance, and the Δx/Δy breakdown. Works with or without axis calibration.

Measure angle on any image

Click a vertex and two arm points to read the angle in degrees. With axes calibrated you also get the angle in data coordinates.

What PlotExtract includes

Calibrated coordinates

Set two points on each axis (linear or log scale) and every click returns real data values.

Multiple series

Add, rename, reorder and color-code as many series as you need. Export each or all at once.

Distance & angle

Measure pixel or calibrated distances and angles directly on the plot. No external tool needed.

No account required

Open the tool and start working. No sign-up, no login, no email address.

Undo anything

Ctrl+Z undoes point additions, moves, deletions and series removal. Up to 50 steps back.

Runs in your browser

Your image never leaves your computer. Everything is processed locally. Fast and private.

CSV export

Download the active series or all series combined as a clean CSV, ready for Excel, Python, or R.

Shift-key axis alignment

Hold Shift while calibrating to snap to perfectly horizontal or vertical.

Built for anyone working with chart data

If you need numbers out of a chart image, PlotExtract handles it.

Researchers

Extract data from published figures and supplementary plots to compare results or run your own analysis.

Students

Digitize graphs from textbooks, papers, or lecture slides when the underlying data is not available.

Analysts

Pull numbers out of chart screenshots and paste them straight into Excel, Python, or R.

Engineers

Measure distances and angles on technical drawings, microscopy images, or photos with a known scale.

Frequently asked questions

How do I extract data from a plot or graph image?

Open your image in PlotExtract, calibrate the axes by clicking two known points on each axis, then click on each data point in the chart. The tool converts your clicks into real data coordinates and lets you export the result as a CSV file.

What is a plot digitizer?

A plot digitizer (also called a graph digitizer or chart digitizer) is a tool that extracts numerical data from an image of a chart or graph. PlotExtract is a free, browser-based plot digitizer. No software installation or account required.

How do I digitize a graph or chart?

Load the graph image into PlotExtract, set axis calibration points to define the coordinate system, then click each data point you want to capture. The digitized coordinates are shown immediately and can be exported to CSV.

How do I measure a distance on an image?

Switch to Measure mode in PlotExtract, then click a start point and end point. The tool reports the pixel distance and, if you have set a real-world scale, the calibrated distance in your chosen unit (mm, cm, m, etc.).

How do I measure an angle on an image?

In Measure mode, click the vertex of the angle and then two arm points. PlotExtract calculates and displays the angle in degrees. With axis calibration active you also get the angle expressed in data coordinates.

Does PlotExtract support logarithmic axes?

Yes. When calibrating an axis you can choose between linear and logarithmic scale. PlotExtract handles the log transformation automatically so the exported data values are correct.

Is PlotExtract free? Do I need an account?

PlotExtract is completely free and requires no account or sign-up. Open the tool and start digitizing immediately. All processing happens in your browser — your images are never uploaded to any server.

What image formats are supported?

PlotExtract accepts JPEG, PNG, GIF, WebP, and BMP images. You can open files with drag-and-drop, the Open Image button, or paste directly from your clipboard with Ctrl+V.

Start extracting data now

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