OpusDesk Hub Tools

PDF Compressor

Try a local PDF rewrite and compare the actual before-and-after file sizes.

A local PDF rewrite, not image downsampling. Savings are not guaranteed. Password-protected PDFs are rejected. Keep your original and inspect all pages before using the output.

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Upload a PDF to compress

Rewrites a PDF locally; it may become smaller or larger

What this tool does

Rewrite an unencrypted PDF with or without object streams. The output may be smaller, unchanged or larger. This tool does not downsample images, offer image-quality percentages or guarantee a target file size. Keep the original and inspect the output.

How to use PDF Compressor

  1. Choose an unencrypted PDF. Select a local PDF within the displayed application guardrail. Password-protected or malformed files are rejected.
  2. Choose a save mode. Object streams may reduce structural overhead; Plain rewrite saves without them. Neither mode changes image resolution or guarantees savings.
  3. Compare and inspect. Run the rewrite, compare original and output sizes, then download if useful. If the output is larger, retain your original. Check page order, appearance and any advanced features before using the file.

How this tool works

The component loads the PDF in memory and saves a browser-generated copy with or without object streams. Results depend on how the source PDF stores images, fonts, and objects.

  • Engine: pdf-lib document loading and browser-side PDF rewriting
  • Supported input: unencrypted PDF files
  • Output: rewritten PDF download

Worked example

Input: A two-page synthetic PDF with page sizes 300 × 400 and 612 × 792 points

Output: A two-page rewritten PDF preserving those page sizes; savings vary with the source.

Limits, edge cases, and troubleshooting

Use it for a quick local attempt before sharing. If the size barely changes, the document may already be optimized or dominated by compressed scans.

  • The entire PDF must fit in browser memory.
  • Rewriting may increase size. It does not resample images or guarantee preservation of advanced PDF features.

When to use another workflow

Use Ghostscript, Acrobat, or a specialist compressor when you need image downsampling, font controls, archival profiles, or a target file size.

OptionBest forTrade-off
This browser toolQuick, private, one-off workLimited by browser memory and the documented feature set
Desktop or command-line toolBatch jobs and repeatable automationRequires installation and setup

Supported inputs and limits

  • unencrypted PDF files
  • The entire PDF must fit in browser memory.
  • Rewriting may increase size. It does not resample images or guarantee preservation of advanced PDF features.

Frequently asked questions

Do the modes control image quality?

No. The modes change PDF serialization, not JPEG quality or image dimensions. Image-heavy scans may barely shrink or may become larger.

Are all PDF features preserved?

Do not assume that digital signatures, complex forms, bookmarks or accessibility tags will survive a rewrite as intended. Keep the original and use a trusted desktop editor when these features matter.

Is information sent to a server?

Tool inputs are processed in this browser. This product does not use analytics or send your input to an external API. Clicking an external website link still visits that website.

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For a deeper workspace, explore the related OpusDesk Hub Studio.