You've exported a video, compressed a presentation, or rendered a high-res image — and then the platform you're sharing it on rejects it with a size limit error. This happens constantly because every platform sets its own file size limits, and those limits change without notice.
This reference compiles current file size limits across email, messaging, social media, cloud storage, and CMS platforms as of March 2026. More importantly, it explains how to get your files under each limit using the right format and compression settings. A 100MB video that needs to go through Gmail doesn't need a third-party file sharing service — it needs a format conversion and appropriate compression.
Email Attachment Limits
| Provider | Max Attachment Size | Notes |
|---|---|---|
| Gmail | 25 MB | Auto-uploads to Google Drive if larger and shares a link |
| Outlook.com / Microsoft 365 | 20 MB (web) / 150 MB (desktop) | OneDrive link offered for larger files |
| Yahoo Mail | 25 MB | Per-message limit, total including all attachments |
| Apple iCloud Mail | 20 MB email / 5 GB via Mail Drop | Mail Drop links expire after 30 days |
| ProtonMail | 25 MB | Encrypted attachments have additional overhead (~33% for Base64) |
| Zoho Mail | 20 MB (free) / 40 MB (paid) | WorkDrive integration for larger files |
The 25MB Gmail limit is the one most people hit. Base64 encoding for email transport adds ~33% overhead, so a 25MB limit effectively means ~19MB of actual file data. To fit under email limits: convert images from PNG to JPG (typically 5-10x smaller), convert MOV to MP4 with H.264 compression, or convert presentations to PDF (often 50-80% smaller than the source PPTX).
Messaging Platform Limits
| Platform | Images | Video | Documents | Notes |
|---|---|---|---|---|
| 16 MB (auto-compressed) | 2 GB | 2 GB | Images are recompressed; send as document to preserve quality | |
| Discord | 25 MB (free) / 500 MB (Nitro) | 25 MB / 500 MB | 25 MB / 500 MB | Limit applies to all file types equally |
| Telegram | 10 MB (auto-compressed) | 2 GB | 2 GB | Send as file to avoid image recompression |
| Slack | 1 GB | 1 GB | 1 GB | Same limit for all file types on all plans since 2024 |
| Signal | 100 MB | 100 MB | 100 MB | All files capped at 100 MB |
| iMessage | 100 MB (carrier-dependent) | 100 MB | 100 MB | Falls back to MMS (1.5 MB) if iMessage unavailable |
Discord's 25MB free limit is the most frustrating for gamers sharing clips. A 60-second 1080p screen recording is easily 50-100MB as MOV. Converting to MP4 with H.264 and reasonable quality gets it under 25MB: MOV to MP4. For images, PNG to WebP typically cuts file size by 50-70%.
Social Media Platform Limits
| Platform | Image Limits | Video Limits | Notes |
|---|---|---|---|
| Instagram (Feed) | 30 MB (JPG/PNG) | 650 MB / 60 min | Recompresses everything; 1080px max width |
| Instagram (Reels) | — | 650 MB / 15 min | Recommends 9:16 aspect, 1080x1920 |
| YouTube | — | 256 GB / 12 hrs | Largest video platform limit; recommends H.264/MP4 |
| TikTok | — | 287 MB (mobile) / 10 GB (web) | Web upload much more generous; 10 min max |
| Twitter/X | 5 MB (static) / 15 MB (GIF) | 512 MB / 2:20 min | GIFs auto-converted to MP4 on upload |
| 30 MB | 10 GB / 240 min | Recommends H.264 MP4 for best quality | |
| 10 MB | 5 GB / 15 min | Only MP4 format accepted for video | |
| 20 MB | 1 GB / 15 min | Video hosting via Reddit's own player |
Twitter/X's 5MB image limit is the tightest. A high-res PNG screenshot can easily exceed 5MB. Convert to JPG at quality 85 and you'll typically get under 1MB. For Twitter GIFs, the 15MB limit means short, low-resolution only — for longer animations, convert GIF to MP4 first (90%+ size reduction) and upload as video.
Cloud Storage Upload Limits
| Service | Max Single File | Notes |
|---|---|---|
| Google Drive | 5 TB | Limited by storage quota, not file size |
| Dropbox | 2 GB (web) / 350 GB (desktop) | Web upload limit is surprisingly low |
| OneDrive | 250 GB | Was 15 GB until 2023 upgrade |
| iCloud Drive | 50 GB | Per-file limit, separate from storage quota |
| Box | 5 GB (Business) / 50 GB (Enterprise) | Free plan limited to 250 MB per file |
| AWS S3 | 5 TB | Single PUT limited to 5 GB; use multipart for larger |
The Dropbox web upload limit of 2GB catches people off guard — a long 4K video recording easily exceeds it. Use the desktop app for large uploads, or compress first: MKV to MP4 with H.264 often reduces file size by 30-50% from MKV's typical codec configurations.
CMS and Website Platform Limits
| Platform | Default Upload Limit | Configurable? |
|---|---|---|
| WordPress | 50 MB (shared hosting: 2-32 MB) | Yes, via php.ini or .htaccess |
| Squarespace | 20 MB (images) / 300 MB (video) | No |
| Wix | 50 MB (images/docs) / 1 GB (video) | No |
| Shopify | 20 MB (images) / 1 GB (video) | No |
| Webflow | 10 MB (free) / 10 MB (paid) | No (use CDN for larger) |
| Notion | 5 MB (free) / no limit (paid) | Plan-dependent |
WordPress hosting providers are the biggest wildcard. The PHP upload_max_filesize and post_max_size settings vary wildly between hosts (2MB to 256MB). If you're hitting upload limits, optimize images before uploading: PNG to WebP for web delivery or TIFF to JPG for photography sites.
How to Compress Files to Fit Any Limit
When your file exceeds a platform's limit, the right approach depends on the file type:
Images
- PNG over 5MB? Convert to JPG at quality 85. Typical reduction: 80-95%.
- Still too large? Convert to WebP for an additional 25-35% savings over JPG.
- Need transparency? Convert to AVIF — lossy with alpha channel support, dramatically smaller.
- Dimensions too large? Resize first. A 6000x4000 photo scaled to 2000x1333 is 9x fewer pixels before compression even starts.
Video
- MOV/AVI too large? Convert to MP4 with H.264. This alone often halves file size.
- MKV with inefficient codec? Re-encode to MP4 — MKV files often use less-compressed codecs.
- Need to fit under 25MB (Discord)? For a 60s clip: target 3 Mbps bitrate (25MB = 200Mbit / 60s = ~3.3Mbps). Reduce resolution from 1080p to 720p to maintain quality at that bitrate.
- GIF animations? Convert to MP4. A 10MB GIF becomes a 500KB MP4 at equal quality.
Documents
- Large PPTX? Convert to PDF — embedded images get compressed, unused assets stripped. 50-80% reduction is typical.
- PDF too large? Re-export with lower image quality settings, or extract and recompress embedded images.
- Multiple files? Archive as 7Z for best compression, or ZIP for universal compatibility.
- Spreadsheet bloat? Export to CSV if formatting isn't needed — removes all styling overhead.
File size limits exist because platforms need to manage bandwidth, storage, and user experience. Fighting them with workarounds (splitting files, using third-party hosts) adds friction. The better approach is to choose the right format and compression for each platform upfront.
Bookmark this page. The next time you get a "file too large" error, check the limit, pick the right conversion, and move on. Most oversized files are just in the wrong format for the delivery channel.