Compress PDF Online — Free, No Upload Needed

Private by design — runs fully in your browser with pdf.js and pdf-lib. Preview pages, pick quality, and download the smaller PDF.

Upload or Drop your PDF

Drag & drop your PDF here or click to upload
Original Size: N/A

Compression Settings

Higher compression downscales page images more aggressively.
80%
Primarily affects newly rasterised page images.
Compressed Size: N/A
Reduction: N/A

Preview

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Tip: Large, image-heavy PDFs compress more when using High compression with lower image quality.

How to Use:

Drag and drop your PDF file into the area below, or click to upload. Preview your PDF, then select your desired compression level. Our tool will then compress the PDF directly in your browser, ensuring your document's privacy. Once compressed, download the smaller PDF.

Tips to Meet File Size Limits

  • Email: keep attachments under ~25 MB.
  • Online forms/portals: common limits are 5–10 MB.
  • Use High compression and lower image quality for image-heavy PDFs.

How it Works (Client-Side Compression):

This tool uses JavaScript libraries (pdf-lib and pdf.js) to process your PDF file directly within your web browser. This means your PDF never leaves your computer, ensuring maximum privacy and security. Compression is primarily achieved by optimizing images, fonts, and the PDF's internal structure.

*Note on Compression Effectiveness: While this tool performs structural optimizations, significant file size reduction for PDFs with many images often requires advanced image re-encoding (downsampling, lower quality JPEG) which is beyond the scope of simple PDF library operations and may not be fully reflected by the 'Image Quality' slider alone for existing images.

5 Fun Facts about PDF Compression

Fonts can duplicate quietly

Many PDFs embed the same font multiple times. Merging those font subsets can shave megabytes without touching a single pixel.

Hidden bloat

Images aren’t all equal

Vector pages barely shrink—text is tiny already. Scanned pages with JPEG2000 images often compress again if you downscale or re-encode to plain JPEG.

Pick your battles

Linearized ≠ smaller

“Fast web view” (linearization) rearranges bytes for quick first-page loads. It can even add a few KB; it’s about speed, not size.

Speed trade

Thumbnails hitch a ride

Some PDFs store page thumbnails or alternate images for low-res previews. Dropping those extras cuts weight with no visible change.

Invisible luggage

Metadata can be massive

Creator apps sometimes tuck in revision history or XML hundreds of KB long. Stripping metadata can save more than re-encoding a few pictures.

Trim the fat

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