Repair a Corrupted PDF, Free
Repair a PDF that won’t open or says it is damaged. The file is checked first, then rebuilt the least lossy way that works — and you see exactly what was wrong and how many pages came back.
Repair PDF
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Settings appear once you add a PDF.
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Ctrl + Enter runs it ·
Bytes of your files sent anywhere: 0 B · nothing leaves this tab
Every request this page makes is listed as it happens. You’ll see our own code loading, and for some formats a codec engine, but never your file going out.
- Waiting for network activity…
Check it yourself: open your browser’s developer tools on the Network tab, or turn off Wi-Fi once the page has loaded. The tools keep working.
- 100% private Your PDFs never leave this device. Everything runs in your browser.
- No limits No file-size cap, no watermark, no sign-up and no daily quota. Free.
- Batch ready Add as many PDFs as you like; each one is handled and saved in one go.
How to repair a PDF file that won’t open
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Add your PDFs: Drop the damaged PDF. It is checked straight away: whether it is really a PDF, whether it was cut off, and how many pages open as it stands.
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Check the settings: Press Repair PDF. The structure is rebuilt first; if that isn’t enough, intact pages are copied into a new file; only as a last resort are pages rebuilt from pictures of them.
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Save the result: Save the repaired copy and read the report: what was wrong, what was done, and how many pages open now.
Why it doesn’t upload
A PDF that won’t open is often one you can’t afford to lose — a contract, a statement, the only copy of something. Repairing it in your own browser means the damaged file is never handed to a server, and the rescue happens on the device where the file already is.
Check it in your browser’s Network tabWorth knowing
- Missing data can’t be invented. A download cut off at 60% loses whatever came after the cut; the repair recovers everything before it.
- A file that is 0 bytes, a web page, or a ZIP with a .pdf name was never a PDF. The check says which, and what to do instead.
- A PDF that asks for a password is encrypted, not broken. Remove PDF Password handles that when you know the password.
- Rebuilding rewrites the file, so any digital signature in it will show as invalid afterwards. Keep the original if the signature matters.
- The last-resort rebuild from page images keeps the look of each page but not its selectable text, links or form fields.
Under the hood
What happens to your file
The bytes are checked first: an empty file, a web page or a ZIP saved with a .pdf name was never a PDF, and the tool says which it is; junk before the %PDF- header is cut off. A file whose structure is sound is only rewritten cleanly by qpdf. A damaged one is rebuilt with pdf-lib, which reads the file from start to finish instead of trusting its cross-reference table — the index a cut-off download loses — and writes a fresh one. Failing that, pages are copied one by one, skipping any whose objects are gone; and as a last resort, pages pdf.js can still draw are rebuilt as pictures, and the report says their text is no longer selectable. Every result is opened again with pdf.js to count the pages that really open.
Reference: qpdf manual · ISO 32000-2 (PDF 2.0)
Why repair a corrupted PDF in your browser?
A PDF that won’t open is usually damaged in a predictable way: a download cut short, an email attachment truncated, a broken index (the cross-reference table) after a crash. Recovery software sells a download to fix it; many websites ask you to upload the broken file. Here the file is checked first and then rebuilt the least lossy way that works, inside your browser.
You see what was wrong and how many pages came back, so you know whether the repaired copy is complete before you rely on it.
Common reasons a PDF won’t open
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“The file is damaged and could not be repaired”
Acrobat’s most common error usually means a broken index that can be rebuilt.
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Downloads that stopped early
Recover every page before the point where the download was cut.
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Email attachments that arrive broken
Fix files mangled by a mail gateway or a forwarding chain.
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PDFs saved during a crash
Rebuild files left half-written by an app or system crash.
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Files that open blank or partly
Recover readable pages from a file viewers struggle with.
Tips for recovering a damaged PDF
- Try the original source again if you can — re-downloading gets back data a repair can’t invent.
- A file that asks for a password isn’t broken; it’s encrypted.
- A 0-byte file or a web page saved with a .pdf name was never a PDF; the check tells you which.
- Use the last-resort rebuild from page images only when nothing else works; it keeps the look but not selectable text.
- Keep the original: repairing invalidates any digital signature.
Questions
Can a damaged PDF file be repaired?
Usually, yes. Most “damaged” PDFs are intact except for the cross-reference table at the end of the file — the index a reader uses to find each page — and that can be rebuilt from the rest of the file. What can’t be repaired is data that isn’t there: a file cut off halfway loses the pages after the cut.
How do I repair a PDF file that won’t open?
Drop it here and press Repair PDF. It is checked first — you’ll see whether it is really a PDF, whether it was cut off, and how many pages open — then rebuilt and saved as a new copy. Before you start, it is worth trying another reader and re-downloading the file; see why a PDF won’t open.
What does “the file is damaged and could not be repaired” mean?
Acrobat couldn’t find or follow the file’s cross-reference table, so it couldn’t locate the pages. That is very often a download that didn’t finish rather than deep corruption. The full explanation covers what to try, in order.
Will repairing a PDF lose text or formatting?
Not when the structure can be rebuilt, which is the usual case: text, fonts, links and forms are kept exactly. Only the last-resort method — rebuilding pages from pictures of them — loses selectable text, and the report says plainly when that is what happened.
Is it safe to repair a PDF online?
It is here, because the repair runs in your browser: qpdf and pdf.js, compiled to run in the page, work on the file on your own device, and nothing is uploaded. That matters for the kind of file people need rescued — the one copy of a contract or statement.
Can I repair a PDF on a Mac or an iPhone?
Yes. It works in Safari and Chrome on a Mac, and in Safari on an iPhone or iPad: choose the file from Files, repair it, and save the copy back. Very large files are more comfortable on a computer, which has more memory.