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AWE-OS

Compress PDF

Reduce PDF file size by removing metadata and optimising PDF structure.

โœ“ Free ยท No sign-up ยท Works in browserLast updated: March 2026 ยท Tested on Chrome, Firefox, Edge, Safari

Use Compress PDF

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Drop your PDF here

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Max 100 MB

How to Use Compress PDF

  1. Upload your PDF by dragging and dropping it into the drop zone, or click to browse your files.

  2. Select a compression level โ€” Low for a quick resave, Medium for a balanced reduction of metadata and streams, or High for maximum size reduction.

  3. Click "Compress PDF" and wait a moment while the tool processes your file in the browser.

  4. The before/after size panel shows exactly how many bytes were saved. Your compressed PDF downloads automatically.

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About Compress PDF

PDF file sizes can quickly become a problem โ€” Gmail caps attachments at 25 MB, many CMS platforms limit uploads to 10 MB, and cloud storage quotas fill up fast. The AWE-OS PDF Compressor reduces your PDF's size by stripping unnecessary data and optimising the document's internal structure, all without uploading your file anywhere.

The tool works by removing redundant metadata (author, creator, producer fields), eliminating unused cross-reference entries, and applying object stream compression โ€” a technique that packs multiple PDF objects into efficient compressed streams. These structural improvements can reduce file size by 10โ€“40% depending on how the original document was created.

It is important to understand the difference between structural compression and image compression. Browser-based tools can optimise the PDF structure but cannot re-encode embedded images โ€” that requires server-side processing. If your PDF is large primarily because of high-resolution scanned images or photos, the size reduction may be modest. For text-heavy documents, reports, and office files, the results are typically more significant.

After compressing, the before-and-after panel shows your exact savings in bytes and percentage. If the result is not sufficient, consider splitting the PDF into smaller sections using the Split PDF tool, or asking whether every image in the document truly needs its current resolution.

Honest limitation: Heavily image-based PDFs compress well; text-only PDFs may shrink very little because there's little left to compress.

Tips & Best Practices for Compress PDF

  • ๐Ÿ’กStart with Medium compression and check the file size reduction before trying High โ€” most text-heavy PDFs (reports, invoices, forms) achieve 50-70% size reduction at Medium with no visible quality loss.
  • ๐Ÿ’กFor PDFs with many high-resolution photographs or scanned images, High compression gives the best size reduction. For PDFs with only text and vector graphics, the size difference between levels is minimal.
  • ๐Ÿ’กBefore compressing a document for a government portal, check the exact file size limit specified on the portal (commonly 2 MB, 5 MB, or 10 MB) and target well below that limit to avoid upload failures.
  • ๐Ÿ’กCompress PDFs containing scanned bank statements and salary slips before sending by email โ€” a 10 MB scanned document typically compresses to 1-3 MB while remaining fully readable.
  • ๐Ÿ’กIf you need to compress a password-protected PDF, remove the password using the Unlock PDF tool first. The compressor cannot process encrypted files.
  • ๐Ÿ’กAfter compression, always open the output file and visually inspect key pages โ€” especially those with charts, tables, or small printed text โ€” before submitting to ensure the text is still legible.

Common Mistakes to Avoid with Compress PDF

  • โœ•Applying High compression to documents containing fine print, medical reports, or legal contracts โ€” extreme compression can make small text or table borders difficult to read. Use Medium for these document types.
  • โœ•Compressing an already compressed PDF multiple times โ€” repeated compression of a lossy-compressed file degrades quality further without proportionally reducing file size. Compress from the original document whenever possible.
  • โœ•Assuming compression removes document metadata or personal information โ€” compression only reduces visual quality of images to reduce file size. It does not remove embedded names, revision history, or author metadata.
  • โœ•Uploading a 200 MB PDF for compression on mobile data โ€” the file upload itself will consume significant data and time. For very large files, use desktop Wi-Fi for the upload.
  • โœ•Expecting lossless compression for image-heavy scanned PDFs โ€” any significant size reduction for scanned documents involves some degree of image quality reduction. There is no free lunch for scanned content.
  • โœ•Not checking whether the compressed file still meets the required minimum quality standards โ€” some official submissions require a specific minimum DPI (commonly 200 DPI) for scanned pages.

Frequently Asked Questions

How much will the file size actually decrease?
Results vary significantly by file type. PDFs with heavy metadata, unoptimised cross-reference tables, or redundant object streams can shrink by 10โ€“40%. PDFs that are already well-optimised or consist mainly of scanned images will see minimal reduction, because browser-side tools cannot re-encode embedded image data.
Will compression affect my PDF quality?
No visual quality is lost. The tool operates exclusively on the PDF's structural data โ€” removing metadata fields, stripping creator information, and compressing object streams. Text, images, fonts, hyperlinks, and every other piece of visual content remain completely unchanged.
Why did my compressed file end up larger?
Some PDFs are already internally optimised by the software that created them (e.g. Adobe Acrobat). Re-saving through pdf-lib may slightly increase the size in those cases. For PDFs dominated by embedded images that need re-encoding, a server-side compressor with image processing would achieve greater savings.
What is the difference between Low, Medium, and High compression?
Low performs a basic re-save of the PDF structure. Medium also strips all metadata fields (title, author, producer) and enables object stream compression. High applies all Medium optimisations plus maximum stream compression, giving the smallest possible output the browser-side approach allows.
Are my files uploaded anywhere during compression?
No. All compression runs entirely in your browser using pdf-lib. Your PDF is never transmitted to any server, and is discarded when you close the page.
Can I compress a password-protected PDF?
Password-protected PDFs can often still be processed โ€” the tool uses pdf-lib with the ignoreEncryption flag, which allows structure optimisation on many protected files. However, heavily encrypted PDFs may fail. Use the Unlock PDF tool first if you encounter errors.

Built & maintained by Team AWE-OS

This tool is developed in-house and manually re-tested on Chrome, Firefox, Edge, and Safari after every update, following our tool testing policy. Found a bug? Tell us โ€” fixes are usually shipped within days.

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