How to Compress PDF to Send via WhatsApp (Under 100 MB)
WhatsApp allows document attachments up to 100 MB — but slow mobile connections make sending anything over 20 MB painful and it often fails midway. Telegram is more generous at 2 GB, but WhatsApp and LINE are still the dominant messaging apps worldwide where PDF sharing is common. Compressing before sending makes the experience reliable for both sender and receiver.
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Messaging App File Size Limits
| App | Document Limit |
|---|---|
| 100 MB | |
| Telegram | 2 GB |
| Signal | 100 MB |
| iMessage | 100 MB |
| LINE | 300 MB |
| 100 MB |
Practical recommendation: keep PDFs under 20 MB for reliable delivery on mobile networks. Under 5 MB loads near-instantly.
How to Compress a PDF for WhatsApp
- 1
Open PDFBro Compress PDF on your phone
Open pdfbro.tech/tools/compress-pdf in Chrome or Safari on your phone, or on a computer.
- 2
Upload and choose High compression
Upload your PDF and select High compression for maximum size reduction.
- 3
Download and share
Download the compressed PDF. Open WhatsApp → Chat → Attachment (clip icon) → Document → Select the compressed PDF.
Why PDFs Are Large on Mobile
PDFs shared in business contexts are often:
Scanned documents: Each page is a full-resolution image (2–5 MB per page). A 20-page scan = 40–100 MB PDF.
Presentation exports: PowerPoint presentations exported to PDF retain all slide images at full resolution.
Reports from design apps: Marketing reports made in Canva or InDesign export at print quality (300 DPI) — overkill for screen viewing.
All of these compress dramatically with PDFBro's High setting since they're image-heavy.
Pro Tips
- 1
WhatsApp compresses images automatically but not documents — always compress PDFs yourself before sending.
- 2
For price lists and menus shared on WhatsApp Business, keep a permanent compressed version under 5 MB for fast customer downloads.
Frequently Asked Questions
What is WhatsApp's PDF file size limit?
WhatsApp allows document attachments up to 100 MB. For reliable delivery on mobile networks, under 20 MB is recommended.
How small can I compress a PDF for WhatsApp?
For scanned multi-page documents, High compression typically achieves 70–80% reduction. A 50 MB scan can compress to 10–15 MB.
Does WhatsApp compress PDFs automatically?
No. WhatsApp compresses images automatically but sends document files as-is. Always compress before sending.