How to Compress a PDF on iPhone

College applications, visa forms, and government portals almost always cap PDF uploads — often at 1MB or 2MB. A scanned or photo-based PDF blows past that limit fast, and most iPhone owners don’t have a compression tool sitting on their home screen. Grabio’s “Compress PDF” option shrinks a PDF straight from the share sheet in a couple of taps: on-device, free, and with no App Store app to download.

Why PDFs from your iPhone are too big to upload

A PDF made from Notes, a scanning app, or a photo of a signed document is really just a stack of full-resolution images wrapped in a PDF shell. That’s fine for emailing yourself a copy, but a form that caps uploads at 1-2MB will reject it outright. Most people don’t discover this until the upload bar fails, and there’s no built-in “compress” button anywhere in iOS to fix it.

How to compress a PDF on iPhone with Grabio

1. Add Grabio to your iPhone once — it’s a free Apple Shortcut. Get the free Shortcut here and it’s ready in a few seconds.
2. Open the PDF in the Files app (or wherever it’s saved) and tap the Share button.
3. Scroll down the share sheet and tap Grabio.
4. Grabio detects it’s a PDF and opens the PDF menu — tap Compress PDF.
5. A Files save dialog appears so you can pick where to save the smaller file, then Grabio shows “✓ Done — saved to Files.”

Is it private and free on iPhone?

Compression runs using Apple’s native optimizePDF action directly on your iPhone — nothing is uploaded anywhere, so it works even in airplane mode or with no signal. Grabio is 100% free forever: no account, no login, no subscription, no App Store app, and no daily cap on how many times you use it.

Compress PDF on iPhone: FAQ

Does the text stay readable and searchable after compressing?

Yes. Compression reduces the file size of embedded images and optimizes the PDF structure — it doesn’t rasterize or blur any text layer that was already there, so searchable text stays searchable.

Does it work on scanned or photo-based PDFs?

Yes, and that’s where you’ll see the biggest size drop. Scanned pages are usually the reason a PDF is oversized in the first place, since each page is a large image.

Is there a limit on how many pages it can handle?

No page-count limit is set by Grabio. Very large multi-page PDFs may just take a bit longer to process on-device, since everything runs locally on your iPhone’s hardware.

Related on iPhone: turn a photo into a PDF, merge PDF files, or PDF & Document Tools.