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Compress PDF files to reduce size. 4 compression levels — Low, Medium, High, Extreme. 100% browser-based, never uploaded.
PDF Compressor reduces PDF file size by re-rendering each page through PDF.js at lower DPI and re-embedding as JPEG via pdf-lib, with 4 quality presets (Low/Medium/High/Extreme) targeting 50–90% file size reduction.
Reduce PDF file size by 50-90% while keeping readable quality. Choose from 4 compression levels depending on your target file size. All compression runs in your browser — your file never leaves your device.
Drop your PDF onto the upload area.
Pick a compression level (Medium is recommended).
Click Compress and download the smaller file.
Compression flow: PDF.js renders page at chosen scale → canvas.toBlob('image/jpeg', quality) → pdf-lib embedJpg() into a new PDF. Levels: Low (scale 2.0, q=0.9), Medium (1.5, 0.75), High (1.0, 0.5), Extreme (0.75, 0.35). Best results on image-heavy PDFs.
Image-heavy PDFs typically compress 50-90%. Text-only PDFs compress less since text is already efficient. Try Medium first, then High if you need more reduction.
Yes, slightly. We re-encode embedded images as JPG at a lower quality/resolution. Low compression keeps near-original quality; Extreme produces the smallest file but with visible artifacts.