WhisperPDF · Free Compress PDF tool
A scan that's too big for the email limit, a form an upload portal keeps rejecting — shrink it here. Compression runs on your device, so the document you're shrinking is never uploaded anywhere.
It runs on the WhisperPDF homepage — pick “Compress PDF”, drop your file, download the result. Nothing leaves your device at any step.
The PDFs people most need to compress are usually the sensitive ones — tax returns, payslips, ID scans, signed forms — because those are the ones that get emailed and uploaded to portals. Sending that file to a stranger's server just to make it smaller is a bad trade:
It depends on what's inside. Scanned documents and photo-heavy PDFs often shrink by half or more. Text-only PDFs are already small and may barely change — if re-compressing can't help, the tool returns your original untouched and says so.
Text stays sharp. Images are re-rendered at a smaller size, so extreme zoom on photos softens slightly at the strongest level. For reading, printing and emailing, the lighter levels are visually identical for most documents.
Email limits are the classic case — Gmail caps attachments at 25 MB, and many government, school and job portals cap uploads at 2–10 MB. Compressing a scan usually gets it under those lines.
Usually scanned pages: a scanner saves each page as a full-size photo. A ten-page scan can be 30 MB of pictures wrapped in a PDF — which is exactly what compression is best at fixing.
Yes. The file never leaves your device, so there's no uploaded copy to be harvested, leaked or logged — the risk the FBI warned about with upload-based converters doesn't exist here.
Same deal on every one: unlimited, no account, processed on your device.