Repair PDF Online — Recover Pages from Damaged & Corrupt PDF Files Free

Opened a PDF only to find it won't load, displays an error, or shows blank pages? Our free PDF repair tool attempts to recover as many readable pages as possible from damaged, corrupted, truncated, or partially overwritten PDF files. Upload the file, run a damage analysis to see exactly what can be recovered, then download a rebuilt PDF containing all recoverable pages — instantly, privately, in your browser.

The tool uses PDF.js with both standard and lenient parsing modes, inspects the file header and end-of-file marker, and provides a detailed damage report before you commit to recovery. Every step happens locally on your device — your file is never sent to any server.

How to Repair a Damaged PDF — Step by Step

1. Upload your damaged PDF — Drag and drop the file into the upload area or click to browse. Files up to 100 MB are supported. The tool accepts files even if they have incorrect MIME types due to corruption.
2. Review the damage report — Immediately after upload, the tool runs a full analysis: checking the PDF header, end-of-file marker, and attempting both strict and lenient parsing. The report tells you exactly how many pages are recoverable.
3. Choose a recovery mode — Select Auto (tries both modes), Strict (standard parsing), or Lenient (tolerant parsing that ignores structural errors) depending on the severity of the damage.
4. Select pages (optional) — Leave blank to recover all accessible pages, or enter a specific range to recover only the pages you need.
5. Click "Repair & Download PDF" — Each recoverable page is rendered to a clean canvas and assembled into a new PDF. Pages that cannot be rendered receive a labelled blank placeholder so you know exactly which pages were lost.

Three Recovery Modes

🔧 Auto Repair (Recommended)

Tries both strict and lenient parsing automatically and uses whichever mode recovers the most pages. This is the best choice for the majority of damaged files — you get maximum recovery without needing to know the nature of the damage.

🔎 Strict Mode

Uses standard PDF specification parsing. Recovers pages only from structurally intact sections of the file. Best for lightly damaged PDFs — for example, files that were incompletely downloaded or saved, where the early pages are intact but later pages may be missing.

🛠 Lenient Mode

Uses tolerant parsing that actively ignores structural errors, malformed cross-reference tables, and broken object streams. This mode can often extract pages from files that strict mode refuses to open. Use it for heavily corrupted files where Auto mode was unsuccessful.

What the Damage Analysis Checks

📋 PDF Header Validation

A valid PDF must begin with %PDF-. The tool checks for this signature immediately. If it is missing, the file may have been renamed, partially overwritten, or is not actually a PDF — this is flagged in the report.

📄 End-of-File Marker

Valid PDFs end with %%EOF. A missing end-of-file marker indicates the file was truncated — typically caused by an interrupted download, storage failure, or incomplete file transfer. The tool detects and reports this.

🔍 Strict vs Lenient Parse Results

Both parsing modes are attempted and their results compared. If strict parsing fails but lenient succeeds, this tells you the file has structural damage but the page content streams may still be intact — a good sign for recovery.

Key Features

• Automatic damage report: Detailed analysis before any export — header check, EOF check, strict vs lenient parse results, and page count.
• Three recovery modes: Auto, Strict, and Lenient — clearly explained with use-case guidance.
• Blank placeholders for unrecoverable pages: Pages that cannot be rendered are replaced with labelled blank pages so the page count and structure are preserved.
• Recovery summary in download confirmation: Shows exactly how many pages were recovered and how many failed.
• Page range selector: Recover all pages or only a specific subset.
• White background rendering: Each page is rendered on a clean white canvas to eliminate transparency artifacts from corrupt content.
• Quality slider: Control output JPEG quality from 50% to 100%.
• 100% browser-based: PDF.js parses and renders, jsPDF rebuilds the output — nothing leaves your device.
• No watermarks: The repaired PDF contains only recovered content — nothing added.

Common Causes of PDF Damage

🌐 Interrupted Download

A PDF that stopped downloading partway through will be truncated — the first portion of pages may be intact but the rest of the file is missing or zeroed. The tool can often recover the accessible early pages.

💾 Storage Drive Failure

Failing hard drives, corrupted USB drives, and degraded flash storage can introduce random bit errors or zero out sections of a file. Lenient mode can sometimes read around these errors and recover surrounding content.

📧 Email or Transfer Encoding

Incorrect encoding during email transmission, FTP transfer, or copy-paste through certain systems can corrupt binary PDF data. The tool detects header and structure issues caused by encoding problems.

🔄 Incomplete Save / Write

If an application crashed or lost power while writing a PDF, the file may be saved with a valid header but an incomplete body or missing cross-reference table. Lenient mode is often effective at recovering pages from these files.

🗜 Archive or Compression Errors

Extracting a PDF from a corrupt ZIP or RAR archive can produce a truncated or partially correct file. The damage report will identify exactly what is intact and what is missing.

Frequently Asked Questions

Conclusion

Repairing a damaged PDF should be transparent, private, and free. With automatic damage analysis, header and EOF validation, three recovery modes, blank placeholders for unrecoverable pages, a recovery summary, and zero server uploads, this tool gives you the best browser-based repair possible for every common PDF corruption scenario.

No watermarks. No registration. No cost. Scroll up, upload your damaged PDF, review the analysis report, and download as many recovered pages as possible in moments.