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Pdf Compressor

Large PDF files are slow to email, upload, and load. Our PDF compressor reduces file size by re-compressing images at lower quality, removing embedded metadata, and deduplicating repeated objects — without changing the document's visual content at normal screen or print resolution.

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About the PDF Compressor

Large PDF files are slow to email, upload, and load. Our PDF compressor reduces file size by re-compressing images at lower quality, removing embedded metadata, and deduplicating repeated objects — without changing the document's visual content at normal screen or print resolution.

How to use it

  1. Upload a PDF file.
  2. Choose compression level: low (minimal quality loss), medium, or high (maximum size reduction).
  3. Preview the compressed file size before downloading.
  4. Download the compressed PDF.

Formula & methodology

Compression targets: images (typically 60–90% of PDF size) re-encoded at lower JPEG quality (e.g., 150 DPI instead of 300 DPI). Text and vector elements are already compressed; incremental gains from re-encoding. Metadata removal: Creator, Author, GPS, thumbnail strips 1–5%. Object deduplication: identical embedded resources merged. Typical savings: 40–80% for image-heavy PDFs; 5–20% for text-only.

Common use cases

  • Email attachments: reducing a 15MB scanned document to under 5MB
  • Web upload: meeting a site's maximum file size requirement
  • Storage: reducing archive size for document collections
  • Mobile: smaller PDFs load faster on slow mobile connections
  • Print submission: some print services require PDFs under a size limit

Frequently asked questions

Several reasons: (1) the PDF contains high-resolution images that need aggressive downsampling; (2) it has embedded fonts that can't be removed without breaking text; (3) it's a scanned document stored as full-resolution TIFF internally; (4) it uses JBIG2 or CCITT compression that is already optimal. For scanned PDFs, switching the internal image format to JPEG at 150 DPI typically provides the largest gains.
Compression reduces file size (primarily by re-encoding images). Optimization is broader: it includes linearization (web-optimized PDF that loads the first page before the rest downloads), font subsetting (removing unused glyphs), object stream compression (packing multiple small objects), and removing redundant or unused resources. Adobe Acrobat's "Save As Optimized PDF" applies all these; basic compressors apply only image re-encoding.

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