pdfviz

Repair a PDF

or drop one here
Choose a PDF file first.

A PDF that will not open sometimes still holds readable pages behind a broken file structure. This tool opens what it can still read in your browser, writes a fresh copy, and opens that copy again to prove it. If the pages come back, you download them. If the file will not open at all, the tool says so instead of guessing.

How to repair a PDF online

  1. Choose the damaged PDF

    Press Choose a PDF, or drop one on the page. The file stays in this browser tab and is never uploaded.

  2. Repair the file structure

    Press Repair PDF. The tool opens the damaged file, writes a fresh copy of whatever still opens, and prepares it for the output check.

  3. Wait for the output check

    The repaired file is opened again and its pages, page sizes and selectable text are compared with the readable source.

  4. Download the repaired PDF

    Download appears only after the rebuilt file passes its checks. The original file is never changed.

What a rebuild reaches, and what it cannot

A PDF keeps its pages in numbered objects and keeps a table at the end of the file that records the byte offset of every one of them. A reader jumps to that table first. When the table is wrong, the reader has no map, so it reports a damaged file even though every page is still sitting in the bytes. Repairing means loading whatever the library can still open and writing it out as a fresh, correct file.

That is the whole job: the repair opens the damaged file, writes a fresh copy of whatever still opens, and checks the copy before offering it. It does not recover pages that are genuinely missing from the file. If the bytes are gone, no tool can bring them back. A file cut short by an interrupted download is outside this repair: download it again first, then repair the complete copy if it still will not open.

After a successful repair, you may want to remove metadata or run a privacy scan to clean the file before sharing. If the repaired file is large, compress it. If it is password-protected and you know the password, unlock it to run further tools.

When you need to repair a PDF

A PDF that will not open. The reader reports the file as damaged although it downloaded completely. A fresh copy written from what still opens can fix it.

A truncated download. If the download stopped early, the file is incomplete and this repair refuses it. Download the file again first; if the complete copy still will not open, repair that copy here.

A sync or cloud-storage error. Cloud sync sometimes corrupts the file index. Repair the local copy before discarding it.

An email attachment that arrived broken. Save the attachment, repair it here, then split or merge as needed.

A file from an old backup. Backups restored from damaged media may have broken indexes. Run the repair to recover what is still in the bytes.

A PDF that opens in one reader but not another. Some readers are stricter about file structure. A fresh copy may satisfy the stricter reader.

How PDF repair rebuilds the file

A PDF is a collection of numbered objects - pages, fonts, images, text streams - stored at specific byte offsets in the file. At the end of the file sits the cross-reference table, an index that maps each object number to its byte position. A reader opens the file, jumps to the table and uses it to find every object. When the table is wrong or missing, the reader has no map and reports the file as damaged.

This tool loads the damaged file with a PDF library, saves a fresh copy, and opens that copy again. It does not guess what should be there: only content the library can still open makes it into the new file. If the pages open in the fresh copy and match the readable source, the check passes and you can download.

The repaired file is then opened again and its pages, page sizes and selectable text are compared with the readable source. If the rebuild recovered the content, the check passes and you can download. If not, the tool tells you plainly rather than handing you a file that looks openable but is actually broken inside.

Questions about repairing PDFs

Is my PDF uploaded?
No. The repair and verification all run in this browser tab. The file is never sent to a server.
What does the repair do?
It opens the damaged file with a PDF library and saves a fresh copy, then reopens the copy and checks it. When the structure is broken but the content still opens, the fresh copy gives the reader a clean file.
Can it recover pages that are missing?
No. If the bytes are gone, no tool can bring them back. The tool tells you when the rebuild found pages and when it did not.
Does it change the original file?
No. The original is never modified. You download a separate repaired copy.
What kinds of damage does it handle?
It handles broken structural data of the kind that stops readers from opening a file. It does not fix corrupted page content or encrypted files.
Can it repair a password-protected PDF?
Not directly. Unlock the file first, then repair the unlocked copy.
How does it verify the result?
The repaired file is opened again and its pages, page sizes and selectable text are compared with the readable source. If the check fails, the tool tells you rather than offering a broken download.
Is there a file or page limit?
There is no server-side cap: processing happens in your browser. Very large files are still bound by your browser tab's memory and may take longer on slower devices.

The other pdfviz tools

All of them run in a browser tab like this one, and none of them needs an account.