Automatically straighten tilted or skewed scanned pages. Auto-detect skew angles with per-page manual fine-tuning. 100% in your browser — your files never leave your device.
PDF files
OneClickPDF's deskew PDF tool straightens tilted or skewed scanned pages directly in your browser, with zero uploads to any server. It automatically detects the skew angle on every page and applies the correction, and for any page that needs adjusting you can fine-tune the angle per page in 0.1° steps before you download. It is completely free, needs no account, works on any device, and your file never leaves your device at any point.
Deskewing a PDF means correcting the tilt or skew in scanned document pages so that text lines run straight and the content appears properly aligned. When you scan a physical document, even a slight misalignment of the paper on the scanner bed produces pages where the text rows sit at a small angle rather than perfectly horizontal. Across a multi-page document this accumulates into a noticeably crooked result that is harder to read, harder to OCR, and less professional to share.
Deskew is distinct from rotation. Rotation corrects large, obvious misalignments such as a page scanned upside down or sideways. Deskewing handles the subtle, fractional-degree tilt that rotation tools cannot address. A page that looks “almost straight” but reads slightly slanted needs deskewing, not rotation.
OneClickPDF detects these small skew angles automatically using a built-in projection-profile algorithm that measures the angle of the text rows on each page (within a ±10° range). For pages where the automatic result needs adjusting, you can fine-tune the correction angle manually for each individual page before downloading.
How it works
Everything runs in your browser. No software installation, no account, and no file upload to any server.
Drop your scanned PDF onto the page or click to browse and select it from your device. The PDF is read entirely within your browser's memory and is never transmitted to any external server at any point — file size is bounded only by your device's available memory, with no enforced upload cap.
The tool automatically analyses each page and detects the skew angle by measuring how far the text rows tilt from horizontal (a projection-profile algorithm, accurate within ±10° of skew). For most scans the detected correction is applied instantly. If a specific page needs adjusting, use the per-page controls — ±1° and ±0.1° buttons, a reset-to-detected button, or a 'set all pages' field — to set the exact angle for that page independently of the others.
Once the pages look straight, download your corrected PDF. Pages you corrected are re-rendered at high resolution and saved with their skew removed; pages left at 0° are copied untouched so they keep their original quality. The whole process runs in your browser — nothing is uploaded, stored, or deleted on any server.
Most online deskew tools offer automatic correction and nothing else. OneClickPDF gives you automatic detection as the starting point and per-page manual control as the fallback — without a paid plan to access either.
The tool analyses every page and automatically calculates the correction angle needed by measuring how far the text rows tilt from horizontal. For standard scans this produces a straight result with no manual work. Detection runs across a ±10° range and ignores pages with no clear text lines so it never invents a correction.
For pages where the automatic detection needs adjusting, set the correction angle for each page independently in 0.1° steps. Nudge with ±1° and ±0.1° buttons, reset back to the detected value, or apply one angle to every page. No other free tool in this comparison offers per-page control without a paid subscription.
Your scanned PDF is processed locally inside your browser using client-side computation. Nothing is uploaded to any external server at any point. This is critical for scanned documents that may contain personal information, medical records, legal paperwork, or financial statements.
Open the tool and start immediately. No sign-up form, no email verification and no hourly task limit. Process as many PDFs as you need in a single session, with file size bounded only by your device's available memory.
Only the pages you actually correct are re-rendered; pages already sitting straight are copied losslessly from the original so they keep their exact vector text and image quality. A 'skip pages at ~0°' option keeps everything that does not need touching untouched.
Deskewing before running OCR significantly improves text-recognition accuracy because OCR engines work best on straight, well-aligned text rows. Straighten your scan here first, then pass the output through OneClickPDF OCR for the best possible text extraction results.
Skewed scans appear across virtually every industry that still handles physical documents. These are the situations where deskewing makes a concrete difference.
Why choose ours?
Most competitors upload your scanned documents to their servers. We detect and fix skew entirely in your browser.
| Feature | Ours | Sejda | AvePDF | i2PDF | DevineTools | PDF24 |
|---|---|---|---|---|---|---|
| Auto-detect angle | OCR only | |||||
| Manual fine-tune | ||||||
| Per-page control | Paid | |||||
| Free & unlimited | 3/hr | 2/6hr | ||||
| No account needed | ||||||
| Files stay in browser | ||||||
| No file size limit | 100MB | 128MB | 100MB |
Competitor information was accurate at time of publication and may have changed.
Pages straightened? run OCR on your scan to pull out the text now that the rows are aligned — or extract images, convert to Word, or compress the file. Every tool runs in your browser, no account required.
Scan to PDF
Use your device camera to scan documents into a PDF.
Rotate PDF
Rotate single pages or the whole PDF by 90°, 180° or 270° to fix sideways or upside-down scans, with a thumbnail of every page.
Crop PDF
Trim margins or resize page content across your PDF.
OCR PDF
Turn scanned PDFs and image files into searchable, editable text using Optical Character Recognition (OCR) for a live preview. Supports 16 languages.
