How to Compress a PDF on iPhone and iPad

Almost all of a large PDF is pictures: scanned pages, photos of receipts, full-resolution images pasted into a report. Text and vector drawings take very little space.

A page scanned at a high resolution in color can weigh several megabytes on its own. That is why a PDF made from phone photos grows so quickly, and why shrinking the images is what makes it smaller.

Not really. In the Files app, touching and holding a PDF and choosing Compress makes a ZIP file. The images in a PDF are already compressed, so the ZIP usually ends up only slightly smaller, and many forms don't accept a ZIP anyway.

If the problem is only an email attachment, Mail can send a large file through Mail Drop, which shares a download link instead of attaching the file. That gets it to the other person, but it does not help with an upload form that has a size limit.

Open Compress PDF, tap Add from Files and pick the PDF. You can also open a PDF in Mail or Files, tap Share and choose File Acture in the list of apps: it opens with the tools that take it.

Under Size, choose Target size and type the size in KB or MB, or pick one from Presets. File Acture re-encodes the images inside the PDF until the file fits. Text and vector graphics stay sharp, so the document still reads like the original.

Choose Quality instead when there is no exact limit: High — smallest file, Medium — balanced or Low — best quality. Tap Compress and the new PDF appears under Results, ready to share.

A PDF that is mostly text has little to remove. When the size you asked for cannot be reached without breaking the pages, File Acture saves the smallest version it can make and says so under the file name, so you know before you send it.

• Grayscale helps scans: turn on Convert images to grayscale for black-and-white documents. It removes color data the page never needed.
• Metadata: Remove document metadata clears the author, the app that made the PDF and similar details.
• Several files: add up to 5 PDFs in one run in the free version; each one is compressed to the same target.
• Locked PDFs: a PDF that needs a password to open has to be unlocked first.

Results go to the Files app, in On My iPhone › File Acture › PDF (On My iPad on an iPad). The original is never changed, so you can try another size if the first one is not right.

Tap Share next to a result to send it by Mail or Messages, save it somewhere else or upload it straight from the share sheet.

A website that compresses PDFs has to receive the whole file first. For a bank statement, a contract or an ID scan, that is a copy you don't control. File Acture compresses on the iPhone itself; the free version only counts runs with the tool's name and anonymous identifiers, never the file or its name.