How to Send Large Files via Email When a File Is Too Large

Gmail caps attachments at 25MB, Outlook.com stops at 25MB and iCloud Mail at 20MB. Exchange Online defaults to 35MB per message and on-premises Exchange Server to 10MB, and administrators can change both. When a file is too large to email, the mail server either bounces the message back or blocks the upload before you can hit send.

These limits exist because email protocols were built for text messages, not heavy binary transfers. Every attachment is encoded into text before transit, so a file sitting right near the 20MB or 25MB ceiling often expands past the receiver's gateway limit and fails to deliver. Video cuts, design packages, slide decks, and project archives routinely pass those thresholds.

Understanding how to send large files via email comes down to two paths: shrink the file so it fits inside the attachment cap, or upload the file to cloud storage and put a share link in the message body. The sections below cover how to share files that are too large for email using compression, built-in mail client cloud links, transfer tools, or a shared workspace when a file is too big to email directly.

Helpful references: Fastio Workspaces, Fastio Collaboration, and Fastio AI.

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More on this subject: File Sharing (155 guides)

Compression reduces file size by removing redundant data, making it a sensible first step. Knowing how to send a ZIP file is also useful when you need to bundle an entire folder of documents, spreadsheets, or uncompressed images into a single attachment.

How to compress a file to send via email on Windows:

1. Right-click the file or folder in File Explorer.
2. Select "Send to" from the menu.
3. Click "Compressed (zipped) folder" and attach the new .zip file to your email.

How to compress files for email on Mac:

1. Control-click or right-click the file or folder in Finder.
2. Select "Compress" to create a .zip archive in the same folder.
3. Check the archive size in Finder and drag it into your email compose window.

Compression can shrink text-heavy files by 70-90%. However, files that are already compressed will not shrink much. MP4 videos, JPEGs, PDFs, and existing ZIP archives are already optimized, so a 100MB video file might only compress to 98MB.

What to do when a zipped file is still too large to email:

If the ZIP is still over the limit, do not waste time re-zipping it. Upload the .zip archive (or the uncompressed project folder) to Google Drive, OneDrive, or a shared workspace such as Fastio, and send a share link in your email instead. Sending a link also avoids corporate mail filters like Gmail and Exchange blocking .zip attachments that contain scripts or password-protected archives. With a Fastio Send share, recipients can preview files in the browser or download the archive from the link without needing an account (organizations start with a 14-day trial on monthly plans, credit card required).

Best for: Documents, spreadsheets, raw images, presentations, and multi-file folders that compress below 20MB to 25MB.

Skip if: Your files are videos, photos, or already compressed formats, or your zipped file is still too large to email.

Most email providers now works alongside cloud storage. Instead of attaching the file directly, you upload it to the cloud and share a link.

Gmail with Google Drive:

• Click the Drive icon in the compose window
• Upload files up to 10GB
• Gmail automatically converts oversized attachments to Drive links

Outlook with OneDrive:

• Click "Attach" then "Browse cloud locations"
• Upload files to OneDrive
• Share as a link instead of attachment

Apple Mail with Mail Drop:

• Attachments over 20MB automatically upload to iCloud
• Recipients get a download link valid for 30 days
• Supports files up to 5GB

This approach is convenient because you're already in your email client. But there are tradeoffs. Recipients need to click an extra link. File access depends on your cloud storage quota. And for sensitive files, you're relying on basic security that may not meet business requirements.

Share Large Files on Fastio

Fastio handles large files with no compression, no splitting, and no expired links. Share securely with clients and collaborators.

Start 14-Day Trial

File transfer services are built specifically for sending large files. You upload your file, get a link, and share it.

Popular options:

• WeTransfer: Up to 10 transfers or 3GB in total every 30 days free, larger transfers on paid plans
• SendAnywhere: Up to 10GB without an account
• Filemail: Up to 5GB free

These services work, but they come with limitations. Free tiers cap your file sizes. Files often expire after 7-14 days. And most importantly, you lose control once the file leaves your hands. Anyone with the link can download it, and you can't revoke access or track who viewed it. For one-off transfers to people you trust, these services are fine. For business use or sensitive content, you need more control.

For teams that regularly share large files, professional cloud storage offers a better approach than email attachments or file transfer services. Instead of sending files as attachments, you share access to files that live in the cloud. This gives you:

Files stay available: Files don't expire after 7 days. Share a project folder once, and collaborators always have access to the latest versions.

Security controls: Set passwords, expiration dates, and view-only permissions. Revoke access instantly if needed. Set up a client portal for external collaborators who need ongoing access.

Activity tracking: See who viewed, downloaded, or shared your files. Audit logs provide accountability for sensitive documents.

Large files just work: Business-grade platforms handle files that would never fit in an email. Video files, design packages, and data archives transfer without compression or splitting. Fastio supports large files, with seats included in every plan. You can invite clients and collaborators without paying extra for each user. Files belong to your organization, not individual accounts, so nothing disappears when someone leaves the team.

When compression isn't enough and you need to use email, you can split a file into smaller parts. Each part stays under the attachment limit.

Using 7-Zip (Windows):

1. Right-click your file
2. Select "7-Zip" then "Add to archive"
3. Set "Split to volumes" to your email's limit (e.g., 20MB)
4. Send each part as a separate email

Using Keka (Mac):

1. Open Keka
2. Drag your file into the app
3. Set the split size
4. Send the resulting parts separately

Recipients need to download all parts and reassemble them using the same tool. This works in a pinch, but it's awkward for everyone involved. If one email gets lost or filtered as spam, the whole transfer fails. Your recipient also needs to know how to merge split archives.

Best for: Emergency situations when you must use email Skip if: You have any other option available

Sometimes the best solution is making the file smaller before sharing. This works well for media files where you don't need maximum quality.

Video: Use Handbrake (free) to reduce resolution from 4K to 1080p, or adjust the bitrate. A 500MB video might shrink to 50MB with minimal visible quality loss.

Images: Export at lower resolution or use JPEG compression. For screenshots and web graphics, PNG to JPEG conversion often cuts size by 80%.

Documents: Export PowerPoint presentations as PDFs. A 50-slide presentation with embedded images might go from 100MB to 15MB.

Audio: Convert WAV to MP3 or reduce the bitrate. A 10-minute WAV file (100MB) becomes a 10MB MP3 at 128kbps. This approach makes sense when you're sharing for review, not final delivery. A client reviewing a video edit doesn't need 4K. A colleague reading a report doesn't need print-resolution images. For final deliverables where quality matters, use a proper file sharing solution instead of degrading your work.

Your best option depends on what you're sending and why.

For quick one-time transfers: Use your email provider's cloud integration (Gmail+Drive, Outlook+OneDrive). It's already there, and recipients know how to use links.

For sensitive business files: Use professional cloud storage with security controls. You need audit trails, access revocation, and password protection.

For ongoing collaboration: Set up shared workspaces instead of sending files back and forth. Everyone accesses the same files, always up to date.

For large media files: Skip compression entirely. Video and image quality suffers, and you'll waste time on a 5% size reduction. Use a platform built for large files.

For emergencies only: Splitting files works but creates friction. Use it as a last resort when nothing else is available. The real issue isn't that your file is too big. Email wasn't designed for file sharing. Every workaround adds friction. The simplest solution is to share links to files that live somewhere accessible, instead of pushing large attachments through a system built for text messages.