The Complete Guide to Making PDFs Smaller
Why are some PDFs so large?
PDFs become large when they contain high-resolution images — usually from scanning documents, embedding photos, or exporting from design software. A single scanned page at 300 DPI can be several megabytes. Multiply that by dozens of pages and you end up with a file that's too big to email or upload.
Compressing a PDF re-renders each page as a smaller image. The text might look slightly less sharp at very low quality settings, but for most purposes — especially scanned documents — the difference is barely noticeable while the file size drops dramatically.
How the pdfcut.app compressor works
When you load a PDF, the tool reads it in your browser using JavaScript. Each page is rendered as an image, compressed to JPEG at your chosen quality level, and reassembled into a new PDF. Because everything runs client-side, there's no upload step and no privacy risk. The quality slider gives you full control: drag left for a smaller file, right for better quality.
Common use cases
- Shrinking a scanned document so it fits within an email attachment size limit (typically 10-25 MB).
- Reducing the size of a photo-heavy report or presentation before uploading to a portal with a file size cap.
- Compressing scanned receipts and invoices for expense submission systems that reject large files.
- Making a multi-page scanned contract or application smaller before submitting it to a government or university website.
Tips for better results
- Start at 70% quality — this gives a big size reduction with minimal visible difference for most scanned documents.
- If the result is still too large, try lowering the quality to 50% or 40%. The file will be much smaller, though fine text may look softer.
- Text-only PDFs (created digitally, not scanned) may not compress well with this tool since they already use efficient text encoding. This tool is designed for image-heavy and scanned PDFs.