Chapters · 2
PDF Repair
Ready
Repair a PDF
Checked and repaired on your device. The file is never uploaded.
PDF repair rebuilds the parts of a PDF that tell a reader where everything is: the cross-reference table, the trailer and the page tree. When those break, a reader refuses the whole file even though the pages are still inside. Drop the PDF into the tool above to find what is broken, rebuild it and download a copy that opens. It runs in your browser, so the file never leaves your computer.
The chapters below explain what the repair fixes, what it can't, and what to try when a PDF still won't open.
01
What the PDF repair fixes
A PDF is a set of numbered objects (pages, fonts, images) plus an index at the end that says where each one starts. Most "damaged" PDFs have intact objects and a broken index. The tool reads every object directly and rebuilds the rest:
- Junk before the PDF: an email or web server header saved at the start of the file. It's removed.
- A file cut short: a download or copy that stopped early. Every complete object is kept; the half-written last one is dropped.
- A broken or missing cross-reference table: rebuilt from the objects actually in the file, including PDFs that pack objects into compressed streams.
- A missing or broken trailer: rebuilt and pointed at the document's catalog.
- Streams with the wrong length: very common in damaged files, and enough to stop some readers. Each length is measured and corrected.
- A broken page tree: a wrong page count, links to pages that are gone, or a catalog that lost its pages. The tree is relinked or rebuilt from the page objects.
The diagnosis lists each problem, which objects it touched, and whether anything was lost.
What it doesn't do
- It doesn't decrypt password-protected PDFs. Their structure can still be repaired, but you need the password to open them.
- It can't bring back pages that were never saved: if the file was cut before a page, that page is gone.
- It doesn't compress PDFs or convert them to other formats.
If it doesn't work
- The tool says the page tree couldn't be rebuilt: no page survived in the file. Look for an earlier copy.
- The repaired PDF opens but some pages are blank: their content was in the part of the file that was lost.
02
Other ways to get the PDF back
If the repair can't save the file, or before you start:
- Get a fresh copy. Download the file again, or ask the sender to send it again. A transfer that stopped early is the most common cause of damage.
- Open it in another reader. Browsers and other PDF apps read damaged files their own way and sometimes open what one reader refuses. If one does, print or save it as a new PDF.
- Recreate it from the source. If you made the PDF from a Word file, a slide deck or a scan, export it again from there.
Fix the file now
Drop the document into the repair tool at the top of this page. It's free, and the file stays on your device.
Troubleshooting
The tool says the file isn't a PDF
It reads the file's first bytes, not its name. A file named .pdf can be a web page, an error message saved by a browser, or another file type. Download it again.
The PDF is password protected
The tool can rebuild its structure, but it won't remove the password. Open the repaired copy with the password.
Questions
Frequently asked questions
Is PDF repair free?
Yes. PDFs up to 50 MB are checked and repaired free, with no account and no daily limit.
Is my PDF uploaded?
No. The repair runs in your browser and the file stays on your computer.
Will the repair change how my PDF looks?
No. Pages, text and images are copied as they are; only the index, the trailer and broken links between objects are rebuilt.
Can it repair a PDF that opens but shows errors?
Often, yes. Wrong stream lengths and broken cross-references cause warnings in some readers and errors in others. If the tool finds no damage, the problem is likely in the reader.