How to Reduce a PDF's File Size on iPhone
A scanned contract, a photo-heavy report, or a form with a few images attached can easily balloon past the file size limit most email providers and web forms allow. You don’t need a laptop to fix that — you can shrink a PDF right from your iPhone.
Why PDFs get oversized in the first place
Most bloated PDFs are that way because of images, not text. A page scanned at full camera resolution, or a document with several embedded photos, carries far more image data than the page actually needs to look sharp on a screen or in print. Recompressing those images is what brings the file size down.
How to reduce file size on your phone
- Open the PDF you want to shrink from your library.
- Find the Reduce File Size tool in the file’s options.
- Run it. PDF Go recompresses the pages in place and creates a smaller version of the document.
- Check the result before sending it anywhere — text and page count stay identical, only the image data is compressed.
What actually changes
Recompressing a PDF reduces the resolution of embedded images, which is invisible for most everyday viewing and printing but does mean it’s a lossy process — it’s a good idea to keep the original around if you ever need a full-resolution version again later. Text stays crisp either way, since text in a PDF isn’t stored as an image.
When you’d want this
- Emailing a document that keeps bouncing back for being too large
- Uploading to a portal with a strict file size limit (many government and HR sites cap uploads at just a few MB)
- Freeing up space if you’re storing a lot of scanned documents locally
After merging, before sending
If you’ve just merged several scanned pages into one file (a common reason PDFs get large in the first place), running Reduce File Size right afterward is usually the fastest way to get back under an attachment limit — no separate app, no uploading your document to a random “compress PDF” website.
