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Compress PDF — Reduce File Size in Your Browser
Shrink PDF file size by 30–70% directly in your browser. Works on scanned documents, photo PDFs, visa application files. Choose quality level. Your PDF never leaves your device.
How PDF compression works (3 steps)
- Load your PDF. The file stays in your browser — nothing is sent to any server. PDF.js (Mozilla's open-source library) reads and renders each page.
- Choose quality. Medium is recommended for most use cases. Low gives the smallest file. High gives the best image quality with less size reduction.
- Compress and download. Each page renders at your quality level and is written into a new, smaller PDF using jsPDF. Download instantly.
Expected compression by PDF type
| PDF type | Low quality | Medium quality | High quality |
|---|---|---|---|
| Scanned document (photo-based) | 75–80% smaller | 55–65% smaller | 30–40% smaller |
| Photo PDF (images + few words) | 70–80% smaller | 50–60% smaller | 30–40% smaller |
| Mixed (text + photos) | 40–60% smaller | 25–45% smaller | 15–30% smaller |
| Text-only PDF (vector) | 10–30% smaller | 5–20% smaller | 0–10% smaller |
FAQ
How does browser-based PDF compression work?
PDF.js renders each page to a canvas, then jsPDF encodes each page as a JPEG at your chosen quality. The result is a new PDF with all pages re-encoded at smaller file size. Your PDF never leaves your device.
How much will my PDF shrink?
Scanned/photo PDFs: 30–80% smaller depending on quality setting. Text-only PDFs compress less (0–30%) since vector text doesn't benefit as much from this approach.
Will the PDF look the same?
At High quality, visually identical to the original for most documents. Medium shows slight softness at high zoom. Low is fully readable but noticeably softer. Text in output is rasterized (not selectable) — this is expected for browser-based compression.
Is it safe to compress sensitive PDFs?
Yes — everything processes in your browser. Your file is never uploaded anywhere. Safer than cloud-based PDF compressors for sensitive documents like visa files, medical records, or legal documents.
PDF still too large after compression?
Try Low quality mode. Or: compress source photos first using the Compress to 200 KB tool, then rebuild the PDF using JPG to PDF. This two-step approach achieves the smallest possible output.
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