How to Send REALLY Big Files by Email

How to Email Large Files

It’s blissfully easy to email a file attachment to someone, unless the file (or group of files) is too big. Then you get a nastygram saying "message file too big" or some other "delivery failed" error telling you that the message was rejected for being too large.

I've had this happen myself when trying to send large PDF files, JPG photos, or even a really short video clip from my mobile phone. So why does it happen, and what can you do about these file size limits? Here's the scoop...

Many email servers are configured to reject messages larger than 25 or so megabytes. That’s an arbitrary limit set by email system administrators decades ago when mail servers were primitive and bandwidth was tiny by today’s standards. File size limits kept the mail from bogging down.

However, the traditional email file size limit hasn’t kept pace with server power, Internet speeds, or the growth of the average file. Ten megabytes is a good-sized word processor document, but it’s just a few seconds of HD video. The 48-megapixel Galaxy S20 Ultra smartphone can take amazing photos, but the resulting image files can be 15 megabytes each. PDF, Powerpoint and software download files can be many times larger. So those “file too large” bounce-backs are more common than they used to be.

Gmail, Yahoo Mail, AOL and Outlook.com (formerly Hotmail) allow you to attach one or more files totalling up to 25 MB in size to an email, but that’s guaranteed to work only if the recipient is also using one of those services. If your “big” file attachment is bound for some other destination, it may be rejected by another server along the way. If you’re sending a file to some other address, it’s best to keep the file size under 10 MB.

But even that’s not small enough by a long shot. Attached files are converted to MIME (Multi-Purpose Internet Mail Extensions) format before they are sent via email. At the receiving end, the text is converted back into its original format. The MIME conversion process adds about 33% to a file’s byte count, so that 10 MB limit really means, “Don’t try to send any file that’s larger than 7.5 MB in its original format.” Gmail’s 25 MB MIME limit becomes 18.75 MB in native format.

One approach to overcoming the photo file size problem is to use an image resizer application such as the free FastStone Photo Resizer, which can compress a batch of digital photos before sending them off. The image quality of a compressed photo is lower than the original, but you might not be able to tell the difference. The Squoosh app works right in your browser, and lets you quickly compare compression ratios visually. You'll be surprised at how slight the difference is in some cases, even with 80 or 90 percent compression.

Alternatives to Email Attachments

Cloud storage provides a way around the file size limitations of email. Instead of sending a file via email, upload it to a cloud service and email just a link to the file to your recipient. The recipient clicks on the link in your email to download or view the file from the cloud. That’s the basic, wonderfully simple idea. Various cloud services and email providers implement and improve upon it in their own ways.

Outlook.com has an "Attach" option on its message-composition menu bar. One of the sub-options is “Browse cloud locations” which will allow you to select a file from OneDrive, Microsoft’s cloud storage service. Click that to select a file already in your OneDrive folder.

Gmail warns you if you’re trying to attach a file larger than 25 MB to an email message and says, “Don’t worry, you can send it using Google Drive.” Click to upload the file to Google Drive; when the upload is complete, Gmail automatically inserts a link to the file in your email message. I tested this with a 74MB video of my grandkids, and it worked seamlessly.

The Dropbox “Share” button on the file management menu and many other cloud storage services is another option. When you share via email, an email message composition form opens up, and Dropbox sends a message with an embedded link to the file you wish to share.

Flickr is another option for photo sharing. You get free space to store up to 1000 photos or videos and you can share a file by email with just a few clicks. Photos can be marked as public or private.

More File Sharing Ideas

Even cloud services have upload size limits, though they may be measured in gigabytes instead of megabytes. If you have a really, really big file you can resort to one of the oldest file-sharing methods that predates the Internet.

Some archive utilities can split a file into smaller pieces and reassemble the pieces into the original file later. A free utility called 7-zip does this neatly and simply, creating sequentially named ZIP format archives of the file’s pieces. To reassemble the pieces, just provide the name of the first archive file in a series. You can split a file into multiple files of any specified size, allowing them to be sent via email or shared via cloud storage service.

That's a little geeky, so there are specialty services that let you upload and share links to very large files. They claim to provide faster file transfer speeds and secure connections. They have to make money somehow so you’ll often find a “premium, ad-free” subscription option with advanced features.

A free account on WeTransfer lets you send files up to 2 GB. A paid account ($12/month) bumps you up to 20 GB. If you just want to send a large file occasionally, you'll probably go with the free account option. MailBigFile is similar, with a 2GB free option, and paid levels for larger files.

DropSend's free plan has no restrictions on file size, but you are limited to 5 sends per month. There are paid Basic, Standard, Pro, and Business plans with additional bells and whistles.

So go ahead, start sharing those multi-megabyte (or multi-gigabyte) photos, videos, documents and spreadsheets that have been languishing on your hard drive. Just take it easy on the "cats doing funny things" variety, there are plenty of those on the Web already. :-)

Your thoughts on this topic are welcome. Post your comment or question below...