Compress a PDF while keeping text readable

Understand stream-preserving and raster compression so you can choose the right tradeoff for a PDF size limit.

Identify whether the PDF is text or scans

Try selecting a sentence in your PDF viewer. A digital document often has selectable text; a scan may contain only page images. Some scans include an OCR text layer, so selection is a useful clue rather than a complete diagnosis.

Keep a source copy. Editing a signed PDF can invalidate its digital signature, and the compressed export should be treated as a new document.

Start with stream-preserving compression

Use the preserve mode in PDF Compressor when text selection and document structure matter. It recompresses eligible PDF streams without turning every page into an image. Already optimized files may become only slightly smaller or even grow; compare the actual output size.

Preserve mode does not implement a full vector colorspace rewrite. Do not select it expecting vector grayscale conversion. Password-protected or unusual documents may require a supported local password workflow before processing.

Use raster mode when its losses are acceptable

Raster mode renders pages and builds a PDF from those images. DPI controls detail: a lower DPI reduces pixels but can make small print harder to read. Inspect thin lines, small text and stamps before deciding that a smaller copy is usable.

Rasterizing may remove selectable text, links, forms and other interactive features. It is unsuitable when the receiving party requires those features. OCR is a separate operation and does not restore the original structure.

Check more than the first page

Open the downloaded PDF and confirm the page count and order. Check the smallest text on several pages, search for a known phrase when text preservation matters, and compare the file size with the receiving site's cap.

If the document is still too large, split it only when separate uploads are allowed. A size limit is not a reason to omit required pages. Large page counts or high DPI can exhaust browser memory, especially on phones.

Tools for this task

PDF Compressor — Reduce image-heavy PDFs with a clear preservation-versus-size choice.
PDF Splitter — Split a document by ranges, every N pages or explicit boundaries.
PDF Text Extractor — Extract selectable text with page boundaries and reading-order choices.