How to Compress a PDF Without Losing Quality
A large PDF can block an email send, fail an upload form or eat storage you do not have. This guide shows you how to compress a PDF online for free — keeping text crisp and images readable — on any device in under a minute.
When should you compress a PDF?
- The file is over 25 MB and your email client will not send it
- A job application portal rejects files over 2 MB
- You want to save storage on your phone or laptop
- A client portal only accepts PDFs under 5 MB
Step 1 — Open the Compress PDF tool
Go to fileio.app/compress-pdf. No account needed to start.
Step 2 — Upload your PDF
Drag your PDF onto the drop zone or click to browse. Files up to 30 GB are accepted. The original is shown immediately with its file size.
Step 3 — Compress and download
Click Compress PDF. The tool shows the original size, the compressed size and the percentage reduction. Click Download to save the smaller file.
Compress PDF now — freeTypical file size reductions
| PDF type | Typical reduction |
|---|---|
| Scanned document (images only) | 50–80% |
| Report with photos and text | 30–60% |
| Text-only document | 10–30% |
| Already-compressed PDF | 5–15% |
Why is my PDF still large after compression?
PDFs that are already compressed — including those exported from modern word processors or already run through a compressor — give the tool less to work with. In that case, try splitting the document into smaller chunks with the Split PDF tool, or reduce the scan resolution at the scanner before generating the PDF.
Will compression affect text quality?
Text and vector graphics are lossless at all compression levels — they look identical to the original. Only embedded raster images are resampled, so heavily illustrated PDFs may show slightly softer images at high compression.
How to compress a PDF on iPhone or Android
Open fileio.app/compress-pdf in Safari or Chrome on your phone. Tap Click to browse, pick the PDF from Files or your file manager, and follow the same steps. No app to install.