PDF compression is not just about making the smallest possible file. A useful compressed PDF should still be readable, printable and acceptable for the place where you need to upload it. The best setting depends on how the PDF was created.
Start by checking the type of PDF
A scanned PDF is usually made of page images. These files often become large because every page contains a photo-like layer. Image-heavy files usually respond well to compression because image quality, resolution and metadata can be reduced. A text-based PDF is different: it already stores text and vector objects efficiently, so it may not reduce much without damaging quality.
Recommended compression workflow
- Open Compress PDF.
- Upload the file and choose the recommended level first.
- Download the result and check headings, stamps, signatures, tables and small text.
- If the file is still too large, try a stronger setting or force-smaller mode for scanned copies.
For official forms, applications and scanned certificates, keep a copy of the original file before compressing. Compression creates a working copy; it should not replace the only version of an important document.
When to use force-smaller mode
Force-smaller mode is useful when normal optimization does not reduce a scan enough. It rebuilds pages as images at a target quality. This can reduce size significantly, but selectable text may be lost. If text selection matters, run Make PDF Searchable after OCR, or keep the preserve-text compression mode.
Common mistakes
Do not compress repeatedly without checking the result. Each strong image recompression can reduce clarity. Also avoid using very low quality for documents with small printed text, stamps, Aadhaar/PAN-style numbers, QR codes, barcodes or signatures.
Related tools
After compression, use PDF Page Counter to confirm page count, Repair PDF if a portal rejects the file, or Merge PDFs if you need to combine multiple compressed documents.