Deskew PDF
π Private by design: your PDF is processed entirely in your browser. Files never upload anywhere.
βΉοΈ Honest note: true automatic deskew is unreliable in a browser, so this tool does it the reliable way. You adjust the angle yourself and check the live preview before applying it.
How to Use the Deskew Tool
Choose your scanned PDF and it loads into the workspace. Use the Prev and Next buttons to pick the page you want to preview, then drag the rotation slider while watching the live preview until text lines run level. For pages that are fully sideways, use the quick 90 degree buttons first, then fine tune with the slider. When the preview looks straight, choose All pages or a custom page list and click Apply Rotation and Download.
The slider moves in 0.1 degree steps across a 20 degree range, which is plenty for typical scanner skew. The preview re-renders instantly as you drag, so you can dial in the exact angle with confidence. If different pages are skewed by different amounts, run the tool once per group of similarly skewed pages using the custom page list each time.
Why Scans Come Out Crooked
Paper rarely feeds perfectly straight. Document feeders pull sheets at slight angles, pages shift on flatbed glass, and bound books never sit flat, so even careful scanning produces pages tilted by one to three degrees. The tilt is easy to miss on screen but becomes obvious in print, and it makes optical character recognition less accurate because OCR engines expect level text lines.
Straightening matters most before archiving or OCR. A level page reads more comfortably, prints more professionally, and gives text recognition software its best chance. Fixing skew right after scanning also saves trouble later: once a crooked PDF is filed, shared or printed, the tilt tends to live on forever. A quick pass through this tool takes seconds and permanently improves the document.
Quality and Privacy Details
Full 90 degree rotations are completely lossless: the tool updates the page rotation flag without touching a single pixel. Fractional deskew angles re-render each page onto a slightly enlarged sheet computed from the exact rotated bounding box, so no content is clipped at the corners. Text that was selectable in the original stays selectable after 90 degree rotations.
Privacy is built in. Preview rendering and rotation happen entirely in your browser with JavaScript, so your scanned documents are never uploaded to a server or visible to anyone else. The original file is never modified: the tool always creates a new PDF, leaving your source scan untouched. This local only approach is ideal for sensitive scans like medical records and legal documents.
Frequently Asked Questions
Why does this tool not detect the skew automatically?
True automatic deskew analyzes page images to find the dominant text angle, which is computationally heavy and unreliable in a browser, especially for pages with photos, tables or sparse text. Rather than guess wrong, this tool takes the honest approach: you see a live preview of the page and adjust the angle yourself with a precise slider. You get full control and can verify the result visually before applying it.
What angle range can I correct?
The fine adjustment slider covers minus 10 to plus 10 degrees in 0.1 degree steps, which handles the slight rotation typical of document feeder and flatbed scans. For pages that are fully sideways or upside down, the quick buttons rotate by 90 degrees or 180 degrees instantly. Combining a quick 90 degree turn with a small slider correction fixes almost any scanning mistake.
Can I rotate only some pages?
Yes. You can apply the rotation to all pages at once, or type a custom page list such as 1, 4-6, 9 to target specific pages. This is useful when only part of a document was scanned crookedly, for example when a few pages were fed through the scanner at an angle while the rest came out straight. Pages you do not list are copied through unchanged.
Will rotating hurt the quality of my scan?
For 90 degree turns, no quality is lost at all: the tool only changes the page rotation flag, leaving every pixel untouched. For fractional angles the page is re-rendered onto a slightly larger sheet so nothing is clipped, which keeps the full content visible. Because the operation is vector aware where possible, text that was already selectable stays selectable for 90 degree rotations.
Is my PDF uploaded to a server?
No. Your file never leaves your device. The preview rendering and the rotation are done entirely inside your web browser using JavaScript, so nothing is uploaded, stored or seen by anyone else. This makes the tool safe for sensitive scanned documents such as medical records, legal filings and identification papers.
What is the difference between deskew and rotate?
Deskew corrects small accidental tilts, usually a few degrees, so text lines run truly horizontal. Rotate turns pages by large fixed steps like 90 or 180 degrees to fix orientation. This tool does both: the slider handles fine deskewing while the quick buttons handle full rotations, and you can combine them in one pass before downloading.