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PDF compression in 2026: what actually shrinks a file

Not all PDFs compress the same way. Text-heavy PDFs are already tiny. Scanned PDFs balloon in size. Here's how compression really works.

28 May 2026 · 6 min read · ToolBharat Team

PDFs are containers. What they contain determines whether compression saves 5% or 95%.

Three kinds of PDF content

  1. **Text and vector graphics** — already extremely compact. Compression rarely helps.
  2. **Embedded images** — biggest lever. Recompressing at lower quality can drop file size by 80%.
  3. **Fonts** — subsetting removes glyphs you don't use.

Recommended workflow

  • Try lossless first (structural cleanup, font subsetting).
  • If still too large, target image DPI — 150 DPI is fine for screens, 300 for print.

A note on scans

Scanned PDFs are essentially image bundles. OCR + re-imaging often shrinks them further than a raw compress.

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