Deskew PDF
Automatically straighten skewed or tilted scanned PDF pages. High-precision angle detection for clean, professional documents. 100% private.
Upload Scanned PDF Files
About This Tool
Scanned documents often come out slightly tilted, making them look unprofessional and difficult for OCR engines to read. Deskew PDF uses Projection Profile Variance Analysis to detect the exact skew angle of your pages and rotate them back to a perfect 0-degree alignment.
The tool works by analyzing the "horizontal flow" of text lines. Whether your scan is off by a fraction of a degree or a noticeable tilt, our algorithm calculates the optimal correction. You can fine-tune the sensitivity threshold and DPI to balance processing speed with surgical precision.
On-Device Image Processing: Straightening pages requires significant computation. We use WebAssembly to perform these heavy rotations locally, so your scanned IDs or legal papers stay on your device.
How to Use
Upload Scanned PDF
Upload the PDF with tilted or crooked pages.
Fine-tune Settings
Set the sensitivity (default 10) and DPI (150 for speed, 300 for precision).
Straighten and Download
Download the corrected, perfectly aligned PDF.
Use Cases
Professional Archiving
Clean up tilted scans of old books or historical records.
Improved OCR
Straighten pages before running OCR to significantly increase text recognition accuracy.
Mobile Capture Fix
Correct photos of documents taken at an angle with a smartphone.
Frequently Asked Questions
What is "Sensitivity Threshold"?
It determines how "aggressive" the tool is at finding tilts. A higher value (20+) will catch very subtle angles, while lower values (1-5) only fix obvious crookedness.
Will my PDF lose quality?
At 300 DPI, the quality loss is virtually invisible to the human eye. The tool uses high-quality interpolation to keep text sharp after rotation.
Does it handle landscape pages?
Yes, the tool detects the primary text direction and adjusts accordingly, preserving the intended orientation.