PDF Compressor
Choose up to 10 PDFs and the tool rebuilds each one on your device: it drops unreachable objects left by earlier saves, optionally removes metadata links and writes a fresh index. This is lossless, so images are not recompressed, and the tool shows the exact size before and after. Nothing is uploaded.
Runs in your browser
Free, no sign-up. The PDF is read and rebuilt in your browser; its bytes are never uploaded. The tool records only anonymous actions such as 'compress' or 'download', never file names or sizes.
PDF Compressor
Compress PDF files in your browser with a safe lossless rebuild.
Files
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Saved
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Output
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This optimizer validates PDF structure, removes safe metadata references, drops unreachable incremental-update objects, and rebuilds the cross-reference table locally. Image-heavy PDFs that are already optimized may not shrink much without a full PDF renderer.
PDF queue
0 completed of 0 files
Upload one or more PDF files to see compression results here.
How to use the PDF Compressor
- Drop PDFs onto the upload area or click it to choose files: up to 10 files of 100 MB each.
- Under Compression settings, keep or untick Remove metadata references, and keep or untick Keep original if rebuild is larger.
- Press Compress All (or compress a single file in the PDF queue).
- Read the Files, Saved and Output figures, and the message on each row: a file that could not shrink says so.
- Download each optimised PDF, then open it to check it looks right before you discard the original.
How it works
What this compressor actually does
The tool reads the PDF's internal objects, removes objects that nothing points to any more (typical after repeated 'save' operations that append changes), strips optional metadata links when you allow it, and writes a clean cross-reference table.
It does not recompress images, subset fonts or convert colour spaces. That is why the result is safe and lossless, and also why a PDF made mostly of scanned pages or large photos may shrink by only a little or not at all.
Which PDFs shrink most
Files that were edited and saved many times in an editor that appends changes, or that carry leftover metadata, tend to benefit. Files exported once from a modern tool, and image-heavy PDFs, are usually already about as small as a lossless rebuild can make them.
If you need a big reduction on a scanned document, you need a tool that downsamples the embedded images; this one deliberately does not.
Metadata removal and the safety check
Remove metadata references drops the XMP /Metadata and /PieceInfo links from object dictionaries where doing so does not change the visible pages. It is not a redaction tool: document text, visible content and the classic info dictionary are not scrubbed.
With Keep original if rebuild is larger ticked (default), a rebuild that is not smaller is discarded and you get the original bytes back, so a download never becomes bigger.
saved % = (original size - output size) / original size x 100
Inputs, outputs and limits
Inputs
- PDF files (checked for the %PDF- header and an %%EOF marker)
- Setting: Remove metadata references (default on)
- Setting: Keep original if rebuild is larger (default on)
Outputs
- One rebuilt PDF per input, or the original when the rebuild is not smaller
- Original size, output size and percentage saved per file, plus totals
Limits
- Up to 10 files per batch and 100 MB per file.
- Encrypted or password-protected PDFs are refused.
- Lossless rebuild only: images, fonts and colours are not recompressed, so scanned or image-heavy PDFs may shrink very little.
- Not a redaction or sanitising tool.
Processing
- The PDF is read and rebuilt in your browser; its bytes are never uploaded. The tool records only anonymous actions such as 'compress' or 'download', never file names or sizes.
Frequently asked questions
Is my PDF uploaded?
No. The file is read into your browser's memory, rebuilt there and offered back as a download. The tool records only that a compression happened, never the file, its name or its size.
Why did my PDF not get smaller?
Most likely it is already tightly packed or dominated by images, which this tool does not recompress. With Keep original if rebuild is larger ticked, you then simply get the original back and the row says it was already optimised.
Will the quality of images drop?
No. The rebuild is lossless: image data is copied as it is. The trade-off is that the savings are modest compared with tools that downsample images.
Can it handle a password-protected PDF?
No. Encrypted PDFs are rejected with a message, because rewriting their structure safely needs the password and a full PDF engine.
Does removing metadata make the PDF anonymous?
No. It removes XMP and PieceInfo links only. Names or details that appear in the page text, annotations or the standard document info are not scrubbed, so do not rely on it for redaction.
Common uses
Need this workflow inside your product?
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