Why PDFs get too big to email
Nine times out of ten, a PDF that's too big to email is too big because it contains high-resolution scanned images. A 12-page contract scanned at 300 DPI on a flatbed scanner can easily hit 30–40 MB. The text itself is a rounding error; the images are everything.
The other 10% of the time the culprit is embedded fonts (rare but possible — especially with custom corporate fonts that include every Unicode glyph), embedded multimedia (a video or audio clip the original author embedded), or a PDF that was exported from PowerPoint with every slide also stored as a hidden full-page image for backward compatibility.
Before you compress, open the PDF and look at it. If it's mostly text and still huge, you've got a weird export issue and no compressor will help much. If it's scans, photos, or screenshots — which is the common case — the techniques below will get you a 5–10× reduction with no visible quality loss.
Attachment limits for the major email providers (2026)
Gmail: 25 MB per message (combined size of all attachments). Above that, Gmail auto-uploads to Google Drive and sends a link instead — fine if you have Drive, useless if you don't or if your recipient's company blocks Drive links.
Outlook.com / Office 365: 20 MB per attachment for most consumer accounts; many enterprise tenants are configured lower. Outlook also has a per-message cap that's separate from the per-attachment cap.
Apple Mail / iCloud: 20 MB on iCloud, but the practical limit is whatever the recipient's server accepts — Apple Mail will happily let you attach a 50 MB file and then bounce it back three hours later.
Corporate Exchange servers: commonly 10 MB or even 5 MB. If you're emailing into a big company (banking, legal, government), assume 10 MB is the ceiling.
Step-by-step: Compress a PDF for email with PrivacyScanPDF
This runs entirely in your browser. No upload, no signup, no watermark, no file left behind on a server because there is no server.
- 1Open the Compress PDF tool (from the homepage, switch the mode dropdown to 'PDF Compress').
- 2Drop in your PDF. The tool reads the file locally and shows you the current size.
- 3Pick a quality preset — 'Email (smallest)' targets ~10 MB and is what most people want; 'Balanced' is for files you'll archive; 'High quality' for print.
- 4Click Compress. The output builds in your browser; download starts automatically when it's done.
- 5Check the output size in your file explorer. If it's still over the limit, re-run with a lower preset or split the PDF first.
What if compressing isn't enough? Split first.
If your PDF is 80 MB and you need to email it to someone with a 10 MB cap, compression alone won't get you there — you'd need a 90% reduction, which would mean visible quality loss on text. The right move is to split the PDF into 5–8 MB chunks and send them as separate messages.
Use the Split PDF tool with page ranges. A 100-page document splits cleanly into five 20-page attachments, each well under any provider's limit. The recipient can re-merge them on their end with the same Merge PDF tool — also free and private.
Things that DON'T work (but people try anyway)
Zipping the PDF. A PDF is already compressed internally; zipping it again typically saves 2–5%, which is rarely enough to matter. We've watched people zip a 26 MB PDF and end up with a 25.1 MB zip — still over the limit.
Printing to PDF as 'Microsoft Print to PDF'. This re-rasterizes the document at screen resolution and can actually INCREASE file size for text-heavy PDFs, because the original vector text becomes a flat image. Only useful if your original was a scanned image PDF and you want to re-encode it.
Taking screenshots of each page. This works in the literal sense but produces an enormous, terrible-quality result and you lose all the text. Don't do this.
When to use a cloud link instead of attaching
If after compressing and splitting you're still over the limit — or if your recipient's IT department quarantines large attachments — upload to a cloud drive and send a link. Google Drive, OneDrive, Dropbox, and Apple iCloud all work. Set the link permission to 'anyone with the link can view' and add an expiry if the provider supports it.
For sensitive documents (anything with PII, financials, or legal content), prefer a link with a password and expiry over an email attachment. Email attachments live forever in sent-mail folders, in backups, and in the recipient's downloads folder. An expiring link is meaningfully more private.