Repair PDF
Fix PDF files that refuse to open or show errors. The tool checks the file structure, rebuilds the cross-reference table and page list, salvages damaged page content and gives you a clean, working copy, with a report of exactly what was wrong. Your files never leave your device.
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How to use the Repair PDF
- Add the damaged PDF by dropping it on the box or clicking to choose one or more files.
- Wait a moment while each file is analysed and rebuilt; large files take a few seconds.
- Read the report to see which problems were found and what was repaired.
- Press Download repaired PDF to save the fixed copy, or Download all as ZIP for several files.
- If pages come out blank, press Try image-based recovery to render whatever is still readable.
What the repair checks and fixes
| Problem | Typical cause | What the tool does |
|---|---|---|
Data before %PDF- | Email gateways, download managers, scripts that print text before the file | Removes the junk so offsets line up again |
Missing %%EOF, cut-off last object | Interrupted download, upload or copy | Drops the incomplete object and rebuilds the index from what is complete |
Wrong startxref or xref offsets | Edited in a text editor, bad incremental save, line-ending conversion (FTP ASCII mode) | Scans all objects and writes a new cross-reference table |
Wrong stream /Length | Line-ending conversion, buggy PDF generators | Finds the real endstream and stores the correct length |
| Broken page tree or catalog | Overwritten objects, crashed editors | Collects every page object and builds a new page list and catalog |
| Damaged compressed page content | Disk or memory errors inside a stream | Keeps the part that still decompresses, so the page opens without errors |
| References to missing objects | Truncation, deleted objects | Removes the dangling references |
Tips for recovering a damaged PDF
- Get a fresh copy first. If the PDF came from a website or email, downloading it again often fixes a truncated file instantly. Compare the file size with the original if you can.
- Check the pages after repair. Open the repaired copy in a PDF viewer and scroll through it. Pages listed as partially recovered may miss content at the end.
- Use image-based recovery for stubborn files. The pdf.js engine tolerates many errors that stop other readers. The result looks like the original but the text is an image.
- Linked pages only by default. PDFs edited many times can contain old versions of pages that are no longer in the page list. Tick "Also recover pages that are not linked" if pages seem to be missing.
- Shrink it afterwards. A repaired file is a clean rewrite; to make it smaller, run it through Compress PDF.
Frequently asked questions
How do I repair a corrupted PDF file?
Drop the PDF into the tool above. It scans every object in the file, rebuilds the cross-reference table and page list, drops unreadable objects and writes a clean copy. Press Download repaired PDF to save it. The report lists every problem it found and what it changed.
Why does my PDF say it is damaged and cannot be repaired?
The most common causes are an interrupted download or upload, which cuts off the end of the file, a broken cross-reference table after editing, extra bytes added by email or file transfer programs, and disk or USB errors that overwrite parts of the file. Most of these leave the page objects intact, so they can be recovered.
Can every PDF be repaired?
No. If the bytes that hold a page's content are missing or overwritten, that content is gone. The tool recovers every page and object that is still readable and tells you which pages were incomplete. A file that is not a PDF at all, or that contains only zeros, cannot be recovered.
What is the cross-reference (xref) table?
It is an index near the end of a PDF that lists the byte position of every object. If it is missing or its offsets are wrong, many readers refuse to open the file. Rebuilding it means scanning the whole file for objects and writing a new, correct index.
What does image-based recovery do?
It renders each readable page with the pdf.js engine, which is very tolerant of errors, and saves the result as a new PDF made of page images. Use it when the normal repair produces blank or broken pages. The text in the result is no longer selectable or searchable.
Is it safe to repair confidential PDFs here?
Yes. The repair runs entirely in your browser with JavaScript. The file is never uploaded, so contracts, statements and other private documents stay on your device.
Can it repair password-protected PDFs?
Encrypted PDFs can be rebuilt structurally, but if text looks garbled afterwards, remove the password first with an unlock tool or use image-based recovery, which can render PDFs that open without a password.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.