How to reduce PDF size without ruining readability
The best compression setting depends on whether the PDF contains real text or scanned page images. Preserving the right content matters more than reaching an unnecessarily small number.
Open Compress PDF →Identify the document type
Try selecting a sentence in your PDF viewer. If the text highlights, the document probably has a text layer. If the whole page behaves like one picture, it is likely a scan.
Text-preserving optimization suits digital documents. Image-based compression can reduce scans more strongly but converts each page to pixels.
Avoid excessive downsampling
Small text, thin lines and faint stamps are the first details to suffer. Use a moderate target and compare the output at normal reading size and at 200 percent zoom.
Colour scans often shrink more when converted to lower-quality page images, but grey handwriting and official seals need extra care.
Keep important features
Choose Automatic or Keep text when copyable text, links or form fields matter. Choose image-based mode only when a flattened visual copy is acceptable.
Any edit can affect an existing digital signature. Keep the signed original if signature validation matters.
Use document structure to help
Remove blank or unnecessary pages before compression. Split a large document only when the receiving workflow accepts multiple files.