Most PDF jobs are small and urgent: a form that wants one file instead of three, an upload limit of 2 MB, a scan that came out sideways, a payslip that needs a password. The usual fix is a website that uploads your documents to someone else’s server. For private paperwork, we think that’s the wrong way round.

Thumbs PDF does the work on your own phone or computer. Pick your files, tap one button, and save the result. Nothing is uploaded, there’s no account, and it keeps working in airplane mode. Here’s how we prove it.

Thumbs PDF is the sister site of Thumbs Photo, which does the same for photos.

Why it’s free

Because your phone does the work, each job costs us almost nothing. That lets us keep the tools free, with no daily limits, no file size caps of our own and no watermarks.

Add it to your home screen

On iPhone, tap the Share button in Safari, then Add to Home Screen. On Android, open the browser menu and choose Install app or Add to Home screen. It opens like an app, works offline, and on Android it appears in the share menu so you can send PDFs straight to it.