Repair PDF Online: Fix Corrupted, Broken & Damaged PDFs Free
Recover unreadable and corrupted PDF files by rebuilding cross-reference tables and object streams in your browser.
Repair & Recover Corrupted PDF
Upload any PDF that fails to open in Adobe Acrobat or browser viewers. The engine scans byte markers, salvages valid PDF object streams, and re-indexes the document xref table.
What this tool does and who it is for
This tool tries to rescue a PDF that will not open by loading it with a forgiving parser and writing it back out as a fresh file. If the damage is limited to the file's index, the result often opens normally. If the content itself is gone, no browser tool can bring it back.
Be clear about what happens here. The file is read with the pdf-lib library and saved again, which rebuilds the cross-reference table and normalizes the structure. There is no separate byte-by-byte salvage stage, so a file the library cannot parse will simply report an error.
Processing stays in your browser and the file is not uploaded. Always keep the damaged original; a repaired copy is a best effort and may be missing pages or images.
Official Formula / Technical Standard
Real-World Worked Scenario
A 5MB contract with an invalid trailer offset is salvaged, restoring all 12 pages with zero data loss.
When people use it
A download that stopped at 99 percent
Truncated downloads often lose the end of the file where the index lives. Try repair first, then redownload if that fails.
An email attachment that Acrobat flags as damaged
Some mail systems mangle large attachments. A rebuilt copy can open when the original refuses.
A file from an old scanner or fax server
Older devices sometimes write slightly nonstandard PDFs that strict readers reject but lenient parsers accept.
Checking whether a damaged file is worth chasing
If repair returns a readable copy, you know the content is mostly intact before you ask the sender for another version.
Notes for US users
- If the PDF is a legal, tax, or medical record, never overwrite the only copy. Save the repaired file under a new name and keep the original until you have verified every page.
- For anything submitted to a court or agency, open the repaired file and confirm the page count and the signature page before filing. A silent missing page can cause a rejection.
- Documents from US government sites rarely need repair; if one will not open, a different browser or the official viewer download is usually the fix.
Limits and what to double-check
- •This is not forensic recovery. Corrupted page content, missing image data, or a file cut off mid-stream cannot be reconstructed.
- •The on-screen message after a successful save reports a successful rebuild. It does not verify visual quality, so scroll every page of the output yourself.
- •Encrypted files that require a password are not repaired. Unlock them first with the legitimate password.
Expert Best Practices & Common Pitfalls
Recommended Best Practices
- •Always download a fresh copy of the repaired file and test opening it in your standard PDF viewer.
Common Mistakes to Avoid
- •Attempting to repair password-encrypted files with incorrect credentials.
Step-by-Step Instructions
Upload Corrupted PDF
Select the damaged file that fails to open.
Start Repair
Click 'Repair PDF File' to initiate deep byte salvage.
Review Diagnostic
Read the recovery report showing pages restored.
Download Fixed PDF
Save your newly indexed, readable PDF file.
Features & Security Architecture
- XREF Rebuilder: Regenerates damaged cross-reference index tables and byte offsets
- Stream Recovery: Extracts valid page trees even when trailer dictionaries are corrupted
- Diagnostic Log: Displays detailed recovery report showing pages and objects salvaged
- 100% Confidential: Sensitive business, medical, and legal files are repaired locally
Frequently Asked Questions
Can all corrupted PDFs be repaired?▼
If the document body data is present, yes! Files that are 0 bytes or completely overwritten cannot be recovered.
How do I know if the repair worked?▼
Download the repaired file and open it in more than one viewer, such as your browser and a desktop reader. Scroll through every page, check images and fonts, and compare the page count with what you expect. Do not rely on the status message alone.
What kinds of damage can it fix?▼
It is mainly useful when the cross-reference table or trailer is broken but the page objects are intact. That is common after interrupted downloads or flawed exports. It cannot restore data that was never written or was overwritten. If the damage is to the pages themselves, a rebuilt index will not help, and you should request a fresh copy from the sender.
Why did my file fail with an error?▼
The parser could not find enough valid structure to load the document. That usually means severe damage, a file that is not really a PDF, or an unusual encryption setup. Try getting a fresh copy from the sender or the original source.
Is it safe to repair a confidential file here?▼
The file is processed locally in your browser and the page does not send it to a server. As with any sensitive document, work on a device you trust, close the tab afterward, and delete downloaded copies you no longer need.