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Deskew scanned pages

Straighten crooked scanned pages automatically or set the angle manually. The output is a raster PDF, nothing is uploaded.

How Deskew scanned pages works

PDF Deskew straightens pages that were scanned at a slight angle, the most common problem with flatbed and automatic-feeder scanners, producing a document where text runs horizontally and columns align cleanly. It works on both scanned-image PDFs and standalone images (JPG, PNG) and is typically the first step before running OCR, since recognition accuracy drops sharply on rotated text.

Deskewing detects the dominant text angle on each page and rotates to correct it; it does not artificially sharpen or enhance the scan. For OCR on the result, use the OCR tool; for straightening a PDF that was printed and re-scanned, combine this with PDF repair. It targets the small involuntary angles a scan introduces (usually under 10 degrees); for a page that is 90 or 180 degrees off, use PDF rotate first.

Frequently asked questions

Why should I deskew before running OCR?

OCR engines recognise text by looking for horizontal character baselines. Even a 2-3 degree tilt significantly raises error rates. Deskewing first means the OCR engine sees straight lines and returns more accurate text.

Does it handle large rotation angles, like a page scanned sideways?

Deskew is designed for small, involuntary angles (typically under 10 degrees) introduced by the physical scan. For a page that is 90 or 180 degrees off, use the PDF rotate tool first.

Will deskewing affect image quality?

Any rotation resamples pixels, which can introduce minimal softening. The correction is applied at the highest quality available; for archival-quality scans, verify the output before discarding the original.

Are my files uploaded to a server?

No. Every operation runs inside your browser tab using JavaScript and WebAssembly. Your file is read into memory on your own device, processed there, and the result is offered as a local download. Nothing is transmitted to Sunasty or any third party. You can verify it yourself: open your browser DevTools, go to the Network tab, and watch, no request carries your file.

Does it work offline?

Yes, once the page has loaded. Because the processing happens on your device, you can disconnect from the network and the tool keeps working. This is the clearest proof that your data never leaves your machine.

Is it free? Do I need an account?

It is completely free and requires no sign-up. There are no watermarks, no daily limits and no tracking cookies needed to use the tool.