WAVESPEED AI PLOT DIGITIZER Runs in your browser

100% FREE

Free Online Plot DigitizerGet the numbers back out of a chart.

Open a chart from a paper, a datasheet or a screenshot, set two points on each axis, and capture its data.
Click points by hand or let it find lines, markers and bars by colour, then export a table.

Log, date and polar axesAutomatic by colourCSV, Excel and JSON

No sign-up No upload Nothing to install

Open a chart

An image, a screenshot from the clipboard, or a page of a PDF.

PNG, JPG, WebP, GIF, BMP or PDF · or paste a screenshot · or a saved project (.json)

Or try an example

Your chart and data stay on your device.Images and PDF in · CSV, Excel and JSON out

THREE SIMPLE STEPS

How to extract data from a graph

Open the chart

Drop an image, paste a screenshot, or open a PDF and pick the page. Crop to the figure if the page holds more than one.

Set the axes

Choose the chart type, click two known points on each axis and type their values. Log, date and polar axes are supported.

Capture and export

Click points by hand or pick the line colour and let it find them. Check the table and download CSV, Excel or JSON.

What it does

Any axis

Linear, logarithmic (base 10) and date axes, in any combination. Scans that are rotated or skewed are handled because the calibration follows the axes, not the page.

Finds data by colour

Pick a line or marker colour, set a tolerance and, if needed, paint the area to search. Lines are sampled at even X steps or along the curve; markers are found by size, and touching ones are split.

Bar, polar and ternary charts

Bar heights are read automatically along the value axis, negative bars included. Polar charts take degrees or radians in either direction; ternary diagrams give the three fractions.

Precise by hand

A magnifier follows the pointer, points can be dragged or nudged with the arrow keys by a pixel or a tenth of one, and every change can be undone.

Check before you export

Turn on the calibrated grid to see the axes you defined drawn over the picture, and see your points joined as a line on top of the original.

Keep your work

The project is saved in your browser as you go, and can be saved as a file with the picture, axes and points to reopen later.

WaveSpeed AI

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Pay as you go

$1 in free credits for eligible new accounts. No card needed. Generators have separate account and credit requirements. The plot digitizer is free.

Plot digitizer FAQ

Is this plot digitizer free?

Yes. There is no account, no watermark and no limit on charts or points. Pictures larger than 30 megapixels are scaled down to 30 megapixels.

Is my chart uploaded?

No. The picture is read and measured in your browser tab. Opening a PDF downloads the PDF reader's font files to your browser, but your file and data are never sent anywhere.

How accurate is it?

As accurate as the picture: positions are measured to a fraction of a pixel. On test charts with known data, automatic extraction was off by about a tenth of a pixel on average for lines and markers, and under half a pixel for bar ends. Most of the error in real use comes from where the axis points are clicked, so zoom in and use the magnifier when you set them.

How do I digitize a log-scale chart?

Choose Log for that axis and click two labelled ticks on it, such as 10 and 1000. Values between them are then read on the log scale. Log axes can't include zero or negative values.

My scan is crooked. Does that matter?

No. Click the axis points where they are on the picture: lines of equal X are taken parallel to the Y axis and vice versa, so rotation and skew are corrected. For warped scans choose "3+ points" and click several points whose X and Y you know; they are fitted together.

How does the automatic extraction work?

It finds the pixels close to the colour you pick, inside the area you paint if you paint one. For lines it takes one point per X step (fitting the line locally so slopes aren't biased) or per column window; for scatter plots it finds each marker's centre; for bar charts it measures each bar's end along the value axis. Gridlines and text of the same colour can be kept out by painting the area to search.

Can I extract data from a chart in a PDF?

Yes. Open the PDF, pick the page and a resolution (300 dpi suits most figures), then crop to the chart. Vector charts in PDFs come out sharp at any resolution.

What does it not do?

It doesn't read numbers from text (axis labels are typed in by you), it doesn't separate lines of the same colour that cross, and it doesn't open SVG or EPS files. Stacked bars are read one colour at a time, each from its own baseline.

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