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Compress PDF

Try lossless browser-side PDF optimization and see the actual size change.

Lossless rebuildMeasured resultRuns in your browserNo upload

What this tool does

Your PDF is parsed and re-serialized with object streams entirely in your browser. This is lossless: images are not recompressed or downscaled, and pages are not rasterized. Whether that produces a smaller file depends on how the PDF was built.

Optimization Results

Every number below is measured from the original file and the rebuilt PDF.

Status: idle

Original size

No file

Upload a PDF first.

Optimized size

Not ready

Shown after the PDF has been rebuilt.

Size saved

Not ready

Original size minus the actual generated size.

Reduction

Not ready

Measured, not estimated.

File validation

Checks file type and size before processing so unsupported files fail early.

Measured results

Savings come from the real generated bytes. If nothing smaller is produced, the tool says so.

Runs in your browser

The PDF is read and rebuilt locally. No file is uploaded and no server processing step is used.

Optimization Insights

Upload a PDF to try lossless browser-side optimization.
Nothing is measured until the PDF has actually been rebuilt in your browser.
Results vary by PDF. Some files shrink, some do not change usefully, and some cannot be improved by this method.
Standard document information fields (title, author, subject, keywords, creator, producer) will be cleared.

What Lossless PDF Optimization Can and Cannot Do

It can

Rebuild the document so objects are packed into object streams.

Drop unreferenced objects left behind by earlier edits and incremental saves.

Clear the standard document information fields when you enable that option.

It cannot

Recompress, downscale, or re-encode the images inside your PDF.

Subset or strip embedded fonts.

Open encrypted or password-protected PDFs.

Guarantee a smaller file. Well-built PDFs often see no useful change.

Privacy and Local Processing Notes

Your PDF is read and rebuilt in your browser.
No file is uploaded and no server or API processing step is used.
No account is required.
Clearing document information is not full sanitization, so do not rely on it to redact a document.
Use care with private documents, IDs, legal files, financial records, medical records, and confidential work files.
Only optimize PDFs you own or have permission to modify.
Review important PDFs after optimization before sharing them.
Large PDFs can be slow or exceed browser memory limits.

Method Explanation

  1. 1. Upload or select a PDF file.
  2. 2. Validate the file type and size.
  3. 3. Read the real bytes of the file in your browser.
  4. 4. Parse the PDF and, if you enabled it, clear the standard document information fields.
  5. 5. Re-serialize the document using object streams.
  6. 6. Measure the actual size of the generated file.
  7. 7. Compare it with the original size and report the real difference.
  8. 8. Offer the generated file for download only when it is genuinely smaller.

Safe Workflow and Related Tools

PDF to JPGExport pages as images when a workflow needs previews.Image to PDFRebuild a simple PDF from optimized JPG pages.Image CompressorShrink large source images before making a PDF.PDF ToolsFind merge, split, unlock, and page-number tools.

Frequently Asked Questions

It performs lossless structural optimization in your browser. The PDF is parsed, rebuilt with object streams, and the real size of the rebuilt file is measured and compared with the original. It does not recompress or downscale images.

Related tools

More tools to try

Merge PDF
PDF Splitter
Rotate PDF
PDF Page Number Adder
PDF Metadata Viewer

Related reading

Learn the formula, assumptions, examples, or context behind this tool.

How PDF compression worksUnderstand what shrinks a PDF and where file size comes from.