Free private PDF utility

PDF Compressor

Rebuild a PDF as compressed page images, compare its size and download the new file without uploading the document to OpenStudyInfo.

Compress a PDF

Maximum 25 MB and 40 pages. This version is best suited to scanned or image-heavy PDFs.
Before compressing: Every page will be rasterised. Searchable/selectable text, links, forms, annotations, attachments, bookmarks and digital signatures may be lost or invalidated.

Processing happens locally in your browser. The PDF processing libraries are loaded from third-party CDNs.

How to compress a PDF online

  1. Choose a PDF no larger than 25 MB.
  2. Select 96 DPI for a smaller file, 120 DPI for balance or 144 DPI for clearer pages.
  3. Set the JPEG quality. Higher quality usually creates a larger file.
  4. Select Compress PDF and keep this browser tab open.
  5. Compare the original and new file sizes.
  6. Download the PDF, open it and inspect small text, photographs and every page.

How this PDF compressor works

The browser renders each PDF page onto a canvas, converts that page to a JPEG image and builds a new PDF from those images. This can substantially reduce some scanned or photo-heavy files because image resolution and quality are controlled.

A PDF containing efficient vector text may already be small. Rasterising such a document can make it larger and removes the advantages of selectable text. The result section warns when the output is not smaller, so you can keep the original instead.

The tool limits processing to 40 pages and caps exceptionally large page canvases to reduce memory pressure on phones. A lower resolution can improve speed, but fine print may become harder to read.

Not lossless: This is an image-based compression method. Do not use it when searchable text, form fields, accessibility tags, legal signatures or exact original PDF structure must be preserved.

Tips for a readable smaller PDF

  • Try the Balanced setting first.
  • Use 96 DPI for simple scans only after checking small text.
  • Use 144 DPI for detailed documents when the upload limit allows it.
  • If the result is larger, retain the original PDF.
  • Never compress your only copy of an important document.
  • Do not process password-protected or digitally signed PDFs here.
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Frequently asked questions

Will this keep selectable text and links?

No. Pages are rebuilt as images, so searchable text, links, forms and other interactive features are not preserved.

Can the compressed PDF become larger?

Yes. A well-optimised text or vector PDF may grow after rasterisation. The result shows both sizes so you can keep the original.

Can I choose an exact target size?

No. DPI, image detail, page count and JPEG quality affect the output, so an exact KB or MB result cannot be guaranteed.

Can it compress a password-protected PDF?

No. Use an authorised unprotected copy. Do not attempt to remove protection from a document you are not permitted to modify.

Is my PDF uploaded or stored?

No. Processing happens inside your browser and OpenStudyInfo does not upload or retain the selected PDF.

OpenStudyInfo is an independent utility provider. Verify the downloaded document before official submission.

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