What usually makes a PDF large?
The biggest cause is high-resolution image data. A scan or phone photo can contain millions of pixels. If every page contains a full-resolution image, a short PDF can easily become tens of megabytes.
Do scanned PDFs use more space than text PDFs?
Usually, yes. A text PDF can store characters and fonts efficiently. A scanned PDF often stores each page as an image, so every page may contain a large JPEG or PNG.
Can I reduce PDF size without deleting content?
Often. Image-heavy PDFs can be rendered at a smaller resolution and recompressed. This can reduce file size substantially while keeping the page visually readable. Always review text, signatures and small details afterward.
Should I remove pages first?
If the PDF contains pages you do not need, removing them is one of the cleanest ways to reduce size because it removes the content entirely. Use Extract PDF Pages when you only need selected pages.
What if an upload portal requires 500KB or 1MB?
Use a target-specific compressor such as Compress PDF to 500KB or Compress PDF under 1MB. Tiny targets are not always achievable without visible quality loss, especially for long scanned documents.
Why can repeated compression make a PDF look bad?
Lossy image compression discards information. Recompressing an already compressed PDF can soften text and images further. Keep the original document and compress from the clean source when possible.
What should I check after compression?
Open the new PDF and verify the page count, readability, signatures, barcodes, QR codes and any small printed text. A smaller file is only useful if the information remains usable.