How to compress a PDF for email without internet
You can compress a PDF with no internet using tools already on your computer. On a Mac, open it in Preview, choose File, Export, and set Quartz Filter to Reduce File Size. On Windows, if the PDF came from Word, save it again as a PDF with "Minimum size" selected. To hit an exact limit such as Gmail's 25 MB, an offline app like WorkOffline compresses to a target size.
Email attachment limits
| Email service | Attachment limit | Bigger files |
|---|---|---|
| Gmail | 25 MB | Sent as a Google Drive link (needs internet) |
| Outlook.com | 20 MB | Shared via OneDrive (needs internet) |
| Work email (Microsoft 365) | Set by your organisation | Ask IT, or share a link |
| iCloud Mail | 20 MB | Mail Drop, up to 5 GB (needs internet) |
Limits checked on [date] against each provider's help pages (see Sources). Every option for bigger files needs a connection, so on a train or a plane, shrinking the file is usually the only way.
Method 1: Mac Preview (free, built in)
- Open the PDF in Preview.
- Choose File, then Export.
- Set Quartz Filter to Reduce File Size, then Save.
Good for: a quick squeeze. Watch out: it can make photos and scans very blurry, and you can't choose a target size.
Method 2: Re-save from Word (Windows or Mac)
- Open the original Word document.
- Choose Save As and pick PDF.
- Select "Minimum size", then Save.
Good for: documents you wrote yourself. Doesn't help: PDFs someone else sent you.
Method 3: WorkOffline (target size, offline)
- Open WorkOffline, choose File tools, then Compress for email, and pick the PDF.
- Pick a preset: Smallest (the default), Balanced, Fit Gmail or Fit Outlook.
- Choose Prepare email to attach the smaller copy to a draft in your own mail app. Press Send and it goes when you have signal.
Good for: most PDFs, on Mac or Windows, with text, links and forms kept as they are. It also works on photos, Office files, videos and audio, and the file always stays in its own format. Compress is included with every ticket, from one flat white. The original file is never changed.
Frequently asked questions
Will compressing a PDF make it unreadable?
Text stays sharp because it is stored as text, not pictures. Photos and scans lose some detail. Aim for the largest size that fits your email limit.
Can I compress a PDF on my phone without internet?
Most phone tools upload the file to a server first, so they need a connection. Check that the app says it works on the device.
Why is my PDF so big?
Usually photos or scanned pages saved at high resolution. A 40 page scan can easily pass 30 MB.
Is it safe to use online PDF compressors for work files?
Online tools upload your document to someone else’s server. For client or confidential files, an offline tool keeps the document on your own computer.
Sources
- [Gmail Help: attachment size limits]
- [Microsoft Support: Outlook.com file size limits]
- [Apple Support: iCloud Mail limits and Mail Drop]
How-to guide from Offline News. No tracking scripts on this page.