For years, the default way to send a file was to attach it to an email. It works, right up until the moment it does not: the file is too big, the message bounces, or it lands in a spam folder and vanishes. That is when people reach for a share link instead.

So which one actually wins? The honest answer is "it depends on the file and the moment." A tiny receipt is fine as an attachment. A 150 MB video folder is not. Knowing where each option shines saves you the frustration of a failed send.

This guide puts the two head to head across the things that matter: size limits, bounce-backs, deliverability, security, and the power to take a file back. You will get a full comparison table and clear scenarios so you always know which to grab.

Key takeaways

  • Email providers cap attachments around 25 MB, and encoding inflates files by roughly a third, so a 20 MB file can still bounce.
  • A share link is just a few dozen characters, whether it points to a 2 MB photo or a 200 MB archive.
  • Only a link can be revoked: set it to expire in 1 hour, 12 hours, 24 hours, 3 days, or 7 days, then the file is deleted.
  • Attachments still win for small files under about 10 MB that belong in the email thread.

Round One: Size Limits

This is the most common reason attachments fail. Most email providers cap attachments at around 25 MB, and some are even stricter.

The hidden encoding tax

Attachments get encoded for email, which inflates them by roughly a third. So a file that looks like 20 MB on your drive can push past the 25 MB limit once it is attached. That is why a file you think is "under the limit" sometimes still bounces.

A share link sidesteps this entirely. The link is just a short web address, a few dozen characters, no matter whether it points to a 2 MB photo or a 200 MB archive. The file lives on a server, and only a copy travels when the recipient clicks. Learn the mechanics in how file sharing works behind the scenes.

Winner: Link. Attachments hit a wall fast; links do not care about size.

Round Two: Bounce-Backs and Deliverability

Even when a file fits, big attachments cause trouble. Mail servers scan them, and heavy or unusual attachments raise red flags.

Here is what can go wrong with a large attachment:

  • The recipient's mailbox is full and rejects it
  • A spam filter quarantines the message because of the attachment
  • The provider silently strips the file to protect the inbox
  • The whole email bounces with a confusing error

A link avoids all of this. A short text link rarely trips spam filters, and it does not care how full the recipient's mailbox is because nothing heavy is being delivered to it. The recipient pulls the file down when they are ready.

Winner: Link, for anything beyond a small file.

Round Three: Security and Control

Once you send an attachment, it is gone from your control. It sits in the recipient's inbox, gets forwarded, and lives in backups forever. You cannot unsend it.

A share link can expire. Set it to 1 hour, 12 hours, 24 hours, 3 days, or 7 days, and after that window the file is deleted and the link stops working. If you sent something to the wrong person, the damage has a built-in time limit. An attachment offers nothing like this. To choose a window, see how long should a share link last.

Encryption in transit

Both good email and good link services encrypt files as they travel. But a link service using HTTPS gives you an easy padlock to check, and expiring links mean the file does not sit around indefinitely waiting to leak.

Winner: Link, thanks to expiration and cleaner control.

Round Four: When Attachments Actually Win

Attachments are not obsolete. For small, everyday files they are often the simpler choice, and there is no reason to overthink it.

Note: An attachment can never be unsent. Once it lands in an inbox it lives in the recipient's mailbox, their forwards, and their backups, so save attachments for files you are fine leaving there for good.

Attachments are the better pick when:

  • The file is small, under about 10 MB
  • The recipient expects it right there in the message
  • You want a permanent record kept inside the email thread
  • You are replying inline and the file is part of the conversation

For a one-page PDF or a single photo, attaching it keeps everything in one place. No extra click, no expiry to worry about. Reach for a link only when the file is big, sensitive, or short-lived.

Winner: Attachment, for small files that belong in the thread.

The Full Comparison

Here is everything side by side so you can decide at a glance.

Factor Share link Email attachment
Max file size Up to 200 MB or more About 25 MB
Risk of bouncing Very low High for big files
Spam filter trouble Rare Common for large files
Can you revoke it Yes, it expires No, it is permanent
Recipient sees it instantly Needs one click Right in the message
Kept in the email record Only the link The full file
Best file size Large or sensitive Small and simple

The pattern is clear: links win on size, deliverability, and control, while attachments win on simplicity for small files. A no-sign-up tool like ShareIt.onl makes the link route as quick as attaching, so the big-file penalty disappears. For the wider view, compare cloud storage vs direct file sharing.

Choose Fast With These Scenarios

Still unsure? Match your situation to one of these and you will have your answer in seconds.

Your situation Best choice
Sending a single small PDF to a coworker Attachment
Sending a 120 MB video to a client Link
Sharing a folder of 40 photos Link (zip first)
Replying with a signed one-page form Attachment
Sending a sensitive file you may need to pull back Link with short expiry
Delivering a big project to a freelancer Link

Notice the pattern: small and simple leans attachment, big or sensitive leans link. When you go the link route, our send large files guide and how to share files online walk you through it, and teams can dig into file sharing for teams and remote work. You can start any share from the homepage.

FAQ

What is the biggest file I can email as an attachment?
Most providers cap attachments around 25 MB, and encoding inflates files by roughly a third, so a 20 MB file can still bounce. For anything larger, a share link is the reliable choice since the link size never changes no matter how big the file is.
Why do my large attachments sometimes never arrive?
Big attachments can bounce from full mailboxes, get caught by spam filters, or be silently stripped by the recipient's provider. A short share link avoids all three because it delivers only a tiny web address, not a heavy file, to the inbox.
Can I take back a file after I send it?
Not with an attachment; once it is in someone's inbox, it stays there. A share link, however, can be set to expire after 1 hour to 7 days, after which the file is deleted and the link stops working, giving you a built-in way to limit access.
Are share links safe to use for private files?
Yes, when the service uses HTTPS encryption and you set a short expiry. Send the link directly to the intended person rather than posting it publicly, and for very sensitive files, zip them with a password for an extra layer of protection.
When should I still just use an attachment?
Stick with an attachment for small files under about 10 MB that the recipient expects in the message, like a one-page PDF or a single photo. Attachments keep everything in one email thread and need no extra click, which is ideal for simple, everyday sends.