A PDF repair tool attempts to recover a corrupted or damaged PDF by reading whatever data is still valid and re-saving it as a clean PDF file. It can recover from minor structural corruption, incomplete downloads, and owner-encrypted files.
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Works on minor corruption and owner-encrypted files
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How to Repair a Corrupted PDF
PDF corruption most often happens during incomplete downloads, interrupted file transfers, or storage errors. When a PDF application refuses to open a file, it sometimes fails on minor structural issues that can be bypassed. This PDF repair tool uses the pdf-lib JavaScript library to attempt opening the file and re-saving it — effectively rebuilding the internal structure from whatever data is still intact.
Step 1: Upload the Damaged PDF
Click "Browse File" or drag the corrupted PDF onto the drop zone. The file is read directly in your browser — it is never sent to any server. Even if the file fails to open in Adobe Reader or Preview, the browser-based library may succeed with a more lenient parsing approach.
Step 2: Choose Encryption Option
The "Ignore owner encryption" toggle is enabled by default. Owner encryption means the PDF has restrictions placed on editing, printing, or copying — but the file is still openable. With this option on, the repair tool can open these files and re-save them without the restrictions. This does NOT bypass user-password encryption — if the file requires a password to open at all, it cannot be repaired without the password.
Step 3: Download the Repaired File
Click "Attempt Repair". The tool tries to load and re-save the PDF using PDFDocument.load(bytes, { ignoreEncryption: true }). On success, it shows how many pages were recovered and offers a download link for repaired.pdf. On failure, the error message explains why the repair could not complete.
What This Cannot Fix
Severe corruption where entire content streams are missing or unreadable cannot be recovered — there is no data to reconstruct from. If more than half the file is missing, repair will fail. For maximum recovery of severely damaged files, specialized desktop tools like PDF-Tools or Foxit PhantomPDF use more aggressive low-level recovery techniques not available in browser JavaScript.
FAQ
Is this tool free?
Yes — PDF Repair is completely free with no account or signup required. Everything runs in your browser.
Is my PDF data private?
Yes. Your files never leave your device. All repair attempts happen locally in your browser using JavaScript. Nothing is sent to a server.
What types of damage can this tool fix?
This tool can repair PDFs with minor structural corruption (like incomplete downloads), PDFs locked with owner-only encryption (where the password restricts editing but not viewing), and files that fail to open due to formatting issues in the cross-reference table.
What types of damage cannot be repaired?
Severe data corruption where page content streams are missing or unreadable cannot be recovered — there is nothing to reconstruct from. If more than half the file's data is missing or the file is not a PDF at all, repair will fail. Encrypted PDFs with a user password also cannot be opened without the password.
What does the 'Ignore encryption' option do?
This option tells the PDF library to attempt to open the file even if it has owner-level encryption (restrictions on editing, printing, or copying). It does not bypass user-password encryption — if the file requires a password to open at all, this option will not help.
Why is the repaired PDF smaller or larger than the original?
The repair process re-saves the entire PDF from scratch using pdf-lib. This rebuilds the internal structure, which may remove redundant data (making the file smaller) or reorganize content differently (making it larger). Page content is not changed.