Compress a PDF on your phone, without an app
The clerk wants the PDF under a few megabytes, you are on the bus and the only computer you have is the phone. You do not need a store app for this. Open this page in Safari or Chrome, tap Choose file, and the phone's own picker shows Files, Downloads, recent documents and the folders of your mail app; pick the PDF and choose a level or a target size.
Options
The compression runs inside the browser, on the phone's processor. Nothing is uploaded, which matters on mobile data: a 40 MB scan is not sent anywhere before it is shrunk, only the small result is saved. On Android it lands in Downloads; on iPhone in Files, under Downloads, from where the share sheet sends it to any chat or mail.
Printing the page to PDF, which both phones offer, does not make a file smaller: it rebuilds the document and can even make it larger. Re-encoding the images inside is the step that shrinks it, and that is what this tool does.
Tips
- Received the PDF on WhatsApp? Open it there, tap the share icon and choose Save to Files (iPhone) or save it to Downloads (Android); then pick it from the file picker here.
- A large scan takes longer on a phone than on a laptop. Keep the screen on and the page in front until the result appears; a tab in the background can be paused by the system.
- Use Continue with under the result to split or protect the compressed file without downloading it in between.
Why it is private
Everything you type or drop here is handled by your browser, on your device. Nothing is uploaded. To verify, open your browser's developer tools, go to the Network tab, and use the tool: you will see no request carrying your data.
Frequently asked questions
- Does this use my mobile data?
- Only to load the page and its engine once, a few megabytes that stay cached. The PDF itself is not uploaded, so compressing a large scan costs no data at all.
- Where is the compressed file?
- Android: the Downloads folder, also listed in the browser's downloads. iPhone: the Files app, Downloads folder, unless Safari was set to save elsewhere. The file keeps its original name.
- Can I compress several PDFs at once on a phone?
- Yes, the tool takes up to 20 files; select several in the picker. On a phone do a few at a time, because each one is held in memory while it is processed.