How to Reduce File Size for Email — PDF, Image, Video Guide | MiOffice
Reduce file sizes for email attachments. Compress PDFs, images, and videos to fit email limits. Gmail 25MB, Outlook 20MB workarounds.
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Email Attachment Limits by Provider
Every email provider imposes a maximum attachment size. If your file exceeds the limit, the email bounces or the provider forces you to use a cloud link. Here are the current limits:
| Email Provider | Max Attachment Size | Cloud Alternative |
|---|---|---|
| Gmail | 25 MB | Google Drive link |
| Outlook / Microsoft 365 | 20 MB | OneDrive link |
| Yahoo Mail | 25 MB | None (blocks large files) |
| ProtonMail | 25 MB | ProtonDrive link |
| Apple Mail (iCloud) | 20 MB | Mail Drop (up to 5 GB) |
Important: These limits apply to the total size of all attachments combined, not per file. If you attach three 8 MB files to a Gmail message, that is 24 MB — technically under the limit but may still fail after base64 encoding adds ~33% overhead. Aim for 18-20 MB total to be safe.
Compress PDFs for Email
PDFs are the most common attachment type and often the largest offenders. Scanned documents, design exports, and reports with embedded images can easily exceed 20 MB. The MiOffice PDF compressor typically reduces PDF size by 50-80% without visible quality loss.
Open the PDF Compressor
Go to the PDF compress tool. No account needed.
Upload Your PDF
Drag and drop the PDF or click to browse. The file stays on your device — no server upload. Select your compression level: low (best quality), medium (balanced), or high (smallest file).
Download the Compressed PDF
The compressor shows you the original and new file size. Download the compressed version and attach it to your email. No watermark is added.
Compress your PDF now
Reduce PDF file size to fit email limits — free, no upload, no watermark.
Compress PDF FreeCompress Images for Email
Modern phone cameras produce 5-15 MB images. Attach three photos and you are already at 30-45 MB — over every provider's limit. The MiOffice image compressor reduces image file sizes while maintaining visual quality.
Open the Image Compressor
Go to the image compress tool. Supports JPG, PNG, WebP, and HEIC.
Drop Multiple Images
You can compress multiple images at once. Drag them all in or select a batch. Adjust the quality slider — 80% is a good balance for email (typically 60-70% smaller with minimal visible difference).
Download Compressed Images
Download individual compressed images or all at once. A 12 MB iPhone photo typically compresses to 1-2 MB at 80% quality.
Compress Videos for Email
Videos are the hardest file type to email. A 30-second 1080p clip can be 50-100 MB. The MiOffice video compressor uses FFmpeg WASM to reduce video size in your browser.
Open the Video Compressor
Go to the video compress tool. Processing happens in your browser via FFmpeg WASM.
Upload and Configure
Drop your video file. Choose compression level or set a target file size. For email, target 15-20 MB. You can also reduce resolution (1080p to 720p) for further savings.
Download Compressed Video
Wait for processing (video compression takes longer than PDF/image). Download the result and attach to your email.
Tip: If the compressed video is still too large for email, consider uploading to a cloud service and sharing the link. For very short clips (under 10 seconds), converting to a GIF or animated WebP can also work.
Additional Tips for Smaller Email Attachments
Batch Compress Before Attaching
If you are sending multiple files, compress each one individually first. A batch of 5 photos at 2 MB each (10 MB total) is much more email-friendly than 5 uncompressed photos at 10 MB each (50 MB).
Use ZIP for Multiple Files
Bundling files into a ZIP archive provides modest additional compression and makes it easier for the recipient to download everything at once. MiOffice has a ZIP tool for this purpose.
Convert to Efficient Formats
PNG screenshots are often 3-5x larger than JPEG equivalents. Converting PNG to JPEG before emailing can save significant space. Similarly, HEIC photos from iPhones should be converted to JPEG for universal compatibility.
Use Cloud Links for Large Files
For files that cannot be compressed below the email limit (large presentations, video projects, archives), upload to Google Drive, OneDrive, Dropbox, or iCloud and share the link in your email instead.
Split Large PDFs
If you need to email a 100-page PDF report, consider splitting it into sections using the PDF splitter and sending in separate emails, or compressing first and splitting only if still too large.
File Size Reference: What Fits in an Email
| File Type | Typical Uncompressed Size | After MiOffice Compression | Fits in Email? |
|---|---|---|---|
| 10-page PDF (text only) | 500 KB - 2 MB | 200 KB - 800 KB | Yes |
| 50-page scanned PDF | 30 - 100 MB | 5 - 20 MB | Usually yes |
| iPhone photo (12 MP) | 5 - 12 MB | 1 - 3 MB | Yes |
| Screenshot (PNG, 1440p) | 2 - 8 MB | 200 KB - 1 MB (as JPEG) | Yes |
| 30-sec video (1080p) | 50 - 100 MB | 10 - 25 MB | Borderline |
| 5-min video (1080p) | 300 - 800 MB | 50 - 150 MB | Use cloud link |
Why Compress in Your Browser?
Most online compression tools upload your file to a server for processing. This works, but it means your potentially sensitive documents — tax returns, contracts, medical forms, financial reports — pass through a third party's infrastructure.
MiOffice compresses PDFs, images, and videos entirely in your browser using WebAssembly. Your files never leave your device. There is no upload, no server processing, and no risk of a third party accessing your documents. For anyone handling confidential files, this is the safest approach.
Related Guides
Frequently Asked Questions
What is the maximum email attachment size for Gmail?
Can I compress a file without losing quality?
What is the best format for emailing images?
How do I compress multiple files for email?
Is it safe to compress sensitive files online?
Why is my PDF so large?
Jay Padimala
CEO & Founder
Jay Padimala is CEO and Founder of MiOffice, a product of JSVV SOLS LLC.
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