Compress PDF documents with advanced optimization and quality settings
Free PDF Compressor — Reduce File Size
Compress PDF documents with advanced optimization and quality settings
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Why your PDF is so big — and what actually gets compressed
PDFs can get huge for a few different reasons, and the fix depends on which one applies to your file. A document exported from Word or a browser is mostly text and shapes — those compress really well. A scanned document is basically a stack of photos, one per page, and those can be 2–4MB each before anything is done to them. Same compression setting, very different results.
What adds the most weight to a PDF
- Scanned pages — each page is a full photo. A 50-page scanned contract can easily be 80–150MB before compression.
- Embedded fonts — the PDF stores the entire font file so it looks right on any computer. Stripping unused characters cuts a good chunk of this.
- High-res photos in reports — a single product photo inserted at original resolution can add 3–5MB to one page.
- Leftover junk data — PDF editors often leave behind deleted objects and old versions of content. Cleaning this up alone can shave 10–20% off the total size.
Which compression level to pick
- Screen
- Smallest file, images at 72 DPI. Fine for reading on screen, not for printing.
- eBook
- 96 DPI — good balance. Reads well on tablets and prints okay at A4.
- Printer
- 150 DPI — solid for home printers and government portal uploads.
- Prepress
- 300 DPI — full print quality, less compression. For commercial print jobs.
Scanned vs. digital PDFs — why results vary so much
If your PDF was created by scanning paper, expect big reductions — 80–90% is normal. If it was exported from Word or a browser, expect 20–50% depending on how many images are in it. Text and shapes compress much more efficiently than photo data, so a clean document without photos won’t shrink as dramatically as a scanned one will.