March 22, 2026
"Your file exceeds the upload limit." Few error messages are more annoying, especially when you have no idea what the limit actually is. This page collects the file size limits for platforms you are most likely to encounter, so you can bookmark it and check back whenever you need to.
Email Services
| Provider | Attachment Limit |
|---|---|
| Gmail | 25MB |
| Outlook / Hotmail | 20MB |
| Yahoo Mail | 25MB |
| Corporate Exchange | Usually 10MB (varies by company) |
| Apple iCloud Mail | 20MB |
One detail that often catches people off guard: email attachments are encoded in Base64, which inflates their size by about 33%. A 19MB file, once attached, takes up roughly 25MB -- right at Gmail's limit. To be safe, keep your attachments at about 75% of the stated limit.
Messaging Apps
| Platform | File Size Limit |
|---|---|
| LINE | ~1GB |
| Facebook Messenger | 100MB |
| 2GB | |
| Telegram | 2GB (free) / 4GB (Premium) |
| Slack | 1GB / file |
| Microsoft Teams | 100MB (inline chat) / 250GB (OneDrive) |
| Discord | 10MB (free) / 50MB (Nitro Basic) / 500MB (Nitro) |
Discord's free tier at 10MB is the strictest among messaging apps -- a single scanned document can easily exceed it. WhatsApp and Telegram have both increased their limits to 2GB, so file size is rarely a concern there. For more details, see our complete guide to messaging app PDF limits.
Job Platforms
| Platform | Upload Limit |
|---|---|
| 5MB | |
| Indeed | 5MB |
| Glassdoor | 5MB |
| Company ATS portals | Usually 2-5MB, sometimes 1MB |
LinkedIn's 5MB cap is one of the tightest you will encounter. If your resume includes design work or photos, it is easy to exceed. For job applications, compressing to under 2MB is the safest approach -- it works on every platform without exception.
Government Portals
| System | Upload Limit |
|---|---|
| Tax filing (Taiwan) | 15MB / household |
| Online document signing | 10MB (body + attachments) |
| National ID / NHI photo | 5MB |
| Inter-agency document exchange | 2MB (body + attachments) |
| Immigration Agency (Taiwan) | 512KB / file |
The Immigration Agency's 512KB limit is the strictest across all platforms. The tax filing system was raised to 15MB starting in 2023. For the full verified breakdown with official sources, see our complete guide to government portal PDF limits.
Education Platforms
| Platform | Upload Limit |
|---|---|
| Moodle (self-hosted) | Default 2MB (PHP default; admin-configurable) |
| MoodleCloud | Hard cap 250MB, default 1MB |
| Canvas LMS | 5GB / file (course quota default 500MB) |
| Turnitin | 100MB, 800 pages max (PDF must have selectable text) |
| Google Classroom | 5TB (via Google Drive) |
Moodle's PHP default of 2MB is the most common bottleneck students hit. Turnitin will reject scanned image-only PDFs (no selectable text). For more details, see our complete guide to school system PDF limits.
Cloud Storage (for Sharing Links)
| Platform | Per-File Limit |
|---|---|
| Google Drive | 5TB |
| Dropbox | 2GB (free) / 50GB (paid) |
| OneDrive | 250GB |
| iCloud Drive | 50GB |
When your PDF exceeds 25MB, sharing a cloud storage link is often a better choice than compressing and emailing. Gmail even suggests switching to Google Drive automatically when your attachment is too large.
The One Rule You Need to Remember
If you do not want to memorize all of this (and who would?), here is one simple guideline: compress your PDF to under 10MB, and it will pass 95% of platform limits. For job applications, go under 2MB. For government uploads, go under 1.5MB.
Use PDF Under's compress tool to set your target size and let the tool find the best quality automatically.