Are my files uploaded when I compress with PDFWix on iPhone?

No. The compression runs entirely in mobile Safari via WebAssembly — your PDF never leaves your phone. The page works offline once loaded, which is a useful proof: nothing is uploading.

Can I compress a PDF stored in iCloud Drive?

Yes. PDFWix's file picker shows iCloud Drive alongside On My iPhone. Pick the file from iCloud, compress, then download — by default Safari saves it to On My iPhone > Downloads. Move it back into iCloud manually if you want to overwrite the original.

How to Compress a PDF on iPhone

A simple step-by-step guide to compress a pdf on iPhone using PDFWix's free online tools.

How it works

Open Safari — Open Safari on your iPhone and navigate to pdfwix.com/compress-pdf.
Pick the PDF — Tap Select file and choose the PDF from Files, iCloud Drive, or Recents.
Choose a quality preset — Pick Recommended, Strong, or Extreme based on how much you need to shrink the file.
Compress and download — Tap Compress PDF, then Download. Safari saves the smaller PDF to Files > Downloads.
Share or move the file — Open Files, long-press the compressed PDF, and Share or move it as needed.

Frequently asked questions

How do I compress a PDF on iPhone without an app?

Open Safari and go to pdfwix.com/compress-pdf. Pick the PDF from Files, choose a quality preset, tap Compress PDF, then Download. The smaller PDF saves back to Files. No app install, free, no daily cap.

Does iOS 18 have a built-in PDF compressor?

No. The Files app, Photos, Safari, and Markup all open or annotate PDFs but cannot compress them. Apple Mail will auto-compress image-heavy attachments on send (above ~5 MB), but the compressed version only exists as the sent email — it isn't saved back to Files.

Is Adobe Acrobat for iOS worth it just to compress PDFs?

Probably not for occasional use. Acrobat Pro on iOS is $9.99/month as of May 2026 and gates compression behind the subscription. PDFWix in Safari handles the same use case for free.