Repair PDF – Fix Files That Won't Open
Rebuild the internal structure of a broken PDF so viewers can open it again. Repair runs in your browser, nothing is uploaded.
- ✓Files never uploaded
- ✓No file limits
- ✓No sign-up
- ✓No watermark
How to Repair PDF
- 1Drop the damaged PDF into the box or click to choose it.
- 2Click Repair PDF.
- 3Download the repaired file and open it to check every page.
Why pdfdots?
Private by design
All processing happens locally in your browser. Your documents are never uploaded to a server, so nobody else can see them.
No limits
No daily task caps, no file-count limits and no premium tier. Process as many PDFs as your device can handle.
Fast
There's no upload or download queue. Work starts the moment you drop a file and finishes at the speed of your own computer.
Works everywhere
Windows, Mac, Linux, iPhone, Android or Chromebook — if it has a modern browser, pdfdots runs on it. Nothing to install.
Why PDFs break and what repair can do
A PDF is not just a stream of pages. It contains an index, the cross-reference table, that tells a viewer where every object in the file begins. When a download is cut short, an email server mangles an attachment or a program writes the file sloppily, that index or the compressed object streams get damaged, and viewers give up with a vague error even though most of the content is still there.
Repair PDF rebuilds that structure with pdf-lib, an open-source JavaScript PDF library that runs directly in your browser. Instead of trusting the damaged cross-reference table, it scans the objects in the file itself, then saves a clean copy with a freshly written cross-reference table and trailer. It handles a wrong startxref pointer, shifted offsets and a truncated or missing trailer. Your document is never uploaded.
Let us be honest about the limits. Repair fixes structure, not missing data. If part of the file is truly gone, for example because only half of it was downloaded, those pages or images cannot be recovered, and the best option is to get the original again. Password-protected files need to be unlocked with Unlock PDF first. After repairing, we recommend opening the result and scrolling through every page before you delete the old copy.
Our take
We try Repair PDF when a file refuses to open with an error like "damaged" or "could not be read", usually after an interrupted download, a failed email attachment or an export from an old scanner or accounting program.
Our routine is simple: repair, open the result, and scroll through every page. If one viewer still complains, we try another one, because some viewers are much stricter than others about small structural errors.
The pitfall: repair rebuilds structure, it cannot invent data. If half of the file was never downloaded, those pages are gone, and the best fix is to fetch the original again.
Related tools
Frequently asked questions
Is my PDF uploaded?+
No. Repair runs in your browser with pdf-lib, an open-source JavaScript library, and the file stays on your device.
What kind of damage can it fix?+
Structural errors that stop viewers from opening the file: a wrong startxref pointer, shifted cross-reference offsets and a truncated or missing trailer.
Can it recover missing pages?+
No. If the data is truly missing or overwritten, it cannot be rebuilt. Download the original again if you can.
Does it work on password-protected PDFs?+
Unlock the file with Unlock PDF first, then repair it.
Will the repaired file look different?+
Normally not. Content is kept as it is; only the internal structure is rewritten.
Is it free?+
Yes. No sign-up, no watermark and no daily limit.